JP4561606B2 - Movie recording apparatus and movie recording method - Google Patents

Description

  The present invention relates to a moving image recording apparatus and a moving image recording method, and can be applied to, for example, a digital video camera. The present invention detects the degree of image quality deterioration due to data compression processing, displays it together with a monitor image, and issues a warning so that the image quality according to the current recording mode can be easily confirmed during shooting. To do.

  Conventionally, a digital video camera, which is a moving picture recording device, compresses moving picture imaging results using MPEG (Moving Picture Experts Group) methods and records it on a recording medium. This data compression is performed by setting the recording mode by the user. The compression rate is switched.

  That is, when the recording mode is set to the LP mode (long play mode), the digital video camera compresses the image pickup result with a high compression rate and records it on the recording medium, thereby recording the image pickup result for a long time. When the recording mode is set to the SP mode (standard play mode), the compression rate is reduced as compared with the LP mode, and the imaging result is compressed, thereby recording the imaging result on the recording medium with high image quality. To do. As a result, the conventional digital video camera is configured to be able to capture a desired subject by switching the recording mode between when priority is given to image quality and when priority is given to recording time.

  In such data compression of the imaging result, a CBR (Constant Bit Rate) method for compressing data so that the generated code amount becomes a constant code amount, and VBR (which changes the generated code amount according to the difficulty of the encoding process). Variable Bit Rate) method is known. In the digital video camera using the VBR system, the maximum bit rate is switched between the SP mode and the LP mode, thereby switching the recordable time and the image quality of the recording medium according to the recording mode.

  Regarding such switching of image quality, for example, Japanese Patent Application Laid-Open No. 11-213524 discloses a process of switching a data compression rate during recording in a moving picture data compression process.

  By the way, in this type of moving image data compression, the image quality varies greatly depending on the processing target. As a result, when a conventional digital video camera shoots a subject with little movement, the imaging result can be recorded with sufficiently high image quality even in the LP mode, whereas when shooting a subject with intense movement such as an athletic meet or sports, In the LP mode, image quality degradation may be noticeable. As a result, when the image is taken in the LP mode as described above, the image quality deteriorates conspicuously. If the remaining capacity of the recording medium is sufficient, the image quality is deteriorated by switching the LP mode to the SP mode and shooting. Can be prevented. On the other hand, if there is little deterioration in image quality even when shooting in LP mode, and the remaining capacity of the recording medium is small, switching the SP mode to LP mode and shooting will give you a valuable shooting opportunity. You can shoot without losing.

  However, the image quality after such data compression processing has a drawback that it is difficult to confirm during shooting, and in practice it can be confirmed only after confirming the imaging result on the monitor device at home.

Thus, if the image quality in the current recording mode can be easily confirmed during recording by shooting, it is considered that the usability of this type of moving picture recording apparatus can be further improved.
JP-A-11-213524

  The present invention has been made in consideration of the above points, and an object of the present invention is to propose a moving image recording apparatus and a moving image recording method capable of easily confirming the image quality according to the current recording mode during shooting.

In order to solve the above-described problem, according to an aspect of the present invention, a video data acquisition unit that captures a subject in a video recording apparatus that records video on a recording medium and acquires video data based on the video, and the video data A display unit that displays a monitor image of a moving image based on the video data acquired by the acquisition unit, a data compression unit that performs data compression processing on the video data acquired by the video data acquisition unit, and outputs encoded data; A recording unit that records the digitized data on the recording medium, a control unit that switches a data compression rate of the data compression processing so as to correspond to the recording mode according to a recording mode instruction by a user, and an image quality of the data compression processing A parameter detection unit that detects a parameter indicating the degree of deterioration, and the display unit is based on the parameter The display indicating the degree of deterioration of the image quality is displayed together with the monitor image, and the data compression unit performs quantization by comparing the upper limit bit rate instructed by the control unit and the generated code amount of the encoded data. By varying the scale, the generated code amount is varied in accordance with the video data within a range not exceeding the upper limit bit rate, and the data compression rate is changed to correspond to the recording mode by switching the upper limit bit rate. The display unit acquires the parameter based on the generated code amount, sets a mark at a position corresponding to the upper limit bit rate, and displays the analog amount according to the parameter, and the degree of deterioration of the image quality The control unit accepts a recording mode instruction from the user by selecting from a plurality of recording modes, Display unit at a position corresponding to the upper limit bit rate in the other recording mode, video recording apparatus is provided for displaying further Marks.

In order to solve the above problem, according to another aspect of the present invention, a video data acquisition step of capturing a subject in a video recording method for recording a video on a recording medium and acquiring video data based on the video, A display step for displaying a monitor image of a moving image based on the video data acquired in the video data acquisition step; a data compression step for outputting encoded data by performing data compression processing on the video data acquired in the video data acquisition step; A recording step of recording the encoded data on the recording medium, a control step of switching a data compression rate of the data compression processing so as to correspond to the recording mode according to a recording mode instruction by a user, and the data compression processing Parameter detection that detects parameters indicating the degree of image quality degradation due to In the display step, a display indicating the degree of deterioration of the image quality is displayed together with the monitor image based on the parameter, and in the data compression step, an instruction is given in the control step. By changing the quantization scale by comparing the upper limit bit rate and the generated code amount of the encoded data, the generated code amount can be changed according to the video data within a range not exceeding the upper limit bit rate, By switching the upper limit bit rate, the data compression rate is changed so as to correspond to the recording mode. In the display step, the parameter is acquired by the generated code amount, and a mark is set at a position corresponding to the upper limit bit rate. The degree of deterioration of the image quality is displayed by displaying the analog amount according to the parameter, and the control scan is performed. In the menu, a user selects a recording mode by selecting from a plurality of recording modes. In the display step, a mark is further set and displayed at a position corresponding to the upper limit bit rate in another recording mode. A video recording method is provided.

  According to the present invention, it is possible to easily check the image quality according to the current recording mode during shooting.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

(1) Configuration of Embodiment FIG. 1 is a block diagram showing a digital video camera which is a moving image recording apparatus according to an embodiment of the present invention. The digital video camera 1 compresses data of an imaging result of a moving image and records it on a recording medium 2.

  That is, in this digital video camera 1, the lens 3 condenses incident light by changing the focus, zoom, and diaphragm under the control of the host controller 4, and the object 3 is focused on the imaging surface of the imaging device provided in the imaging unit 5. An optical image is formed.

  The imaging unit 5 includes, for example, an image sensor using a CCD (Charge Coupled Device) and a peripheral circuit that drives the image sensor and processes an output signal of the image sensor, and is formed on the imaging surface of the image sensor. The optical image is subjected to photoelectric conversion processing, and an imaging result by a moving image is output as a video signal S1.

  The encoder 6 encodes the video signal S1 in the recording mode instructed by the host controller 4, thereby compressing the video signal S1 and outputting encoded data DF. Here, the encoder 6 is an AVC (Advanced Video Coding) encoder based on H264 and MPEG-4 Part 10, and the upper limit bit rate instructed by the host controller 4 by the rate control by the bit rate calculation unit 6A and the control unit 6B. The encoding unit 6C encodes the video signal S1 with the VBR whose upper limit value is limited by the RATE LIMIT.

  That is, as shown in FIG. 2, in the encoding unit 6C, the analog-digital conversion circuit (A / D) 12 performs analog-digital conversion processing on the video signal S1 and outputs image data D1. The screen rearrangement buffer 13 receives the image data D1 output from the analog-digital conversion circuit 12, and the frame of the image data D1 according to the GOP (Group of Pictures) structure related to the encoding process of the encoder 6. Sort and output.

  The subtraction circuit 14 receives the image data D1 output from the screen rearrangement buffer 13, and generates and outputs difference data D2 from the prediction value generated by the intra prediction circuit 15 in intra coding. On the other hand, in inter coding, difference data D2 from the prediction value generated by the motion prediction / compensation circuit 16 is generated and output.

  The orthogonal transform circuit 17 receives the output data D2 from the subtraction circuit 14, performs orthogonal transform processing such as discrete cosine transform and Karhunen-Loeve transform, and outputs transform coefficient data D3 based on the processing result.

  The quantization circuit 18 quantizes the transform coefficient data D3 with the quantization scale QP N specified by the control unit 6B and outputs the result.

  The lossless encoding circuit 20 performs lossless encoding processing on the output data of the quantization circuit 18 by variable length encoding, arithmetic encoding, or the like, and outputs the result. Further, the lossless encoding circuit 20 acquires information related to the intra prediction mode related to intra encoding, information related to a motion vector related to inter encoding, and the like from the intra prediction circuit 15 and the motion prediction / compensation circuit 16, and outputs the information. Set to the index of data D4 and output.

  The accumulation buffer 21 accumulates the output data D4 of the lossless encoding circuit 20 and outputs it at the transmission rate of the subsequent transmission path, whereby the encoding unit 6C outputs the encoded data DF.

  The inverse quantization circuit 23 performs inverse quantization processing on the output data of the quantization circuit 18, thereby reproducing the input data of the quantization circuit 18. The inverse orthogonal transform circuit 24 performs inverse orthogonal transform processing on the output data of the inverse quantization circuit 23, thereby reproducing the input data of the orthogonal transform circuit 17. The deblocking filter 25 removes block distortion from the output data of the inverse orthogonal transform circuit 24 and outputs the result. The frame memory 26 appropriately adds a prediction value generated by the intra prediction circuit 15 or the motion prediction / compensation circuit 16 to the output data of the deblocking filter 25 and records it as reference image information.

  Here, the motion prediction / compensation circuit 16 detects the motion vector of the image data output from the screen rearrangement buffer 13 based on the prediction frame (reference frame) based on the reference image information held in the frame memory 26, and Based on the detected motion vector, the reference image information held in the frame memory 26 is motion-compensated to detect the optimum mode of inter prediction. In addition, when encoding processing is performed by inter prediction, predicted image information is generated in the optimum mode, and a predicted value based on the predicted image information is output to the subtraction circuit 14.

  The intra prediction circuit 15 detects the optimum mode of the intra prediction mode based on the reference image information stored in the frame memory 26 in the intra coding. When encoding is performed by intra prediction, a predicted value of predicted image information is generated from the reference image information in this optimal mode and is output to the subtraction circuit 14.

  The encoding unit 6C detects the optimum mode having the highest coding efficiency from the optimum modes detected by the motion prediction / compensation circuit 16 and the intra prediction circuit 15, respectively, and outputs a prediction value by the detected optimum mode. Then, the operations of the motion prediction / compensation circuit 16 and the intra prediction circuit 15 are controlled, whereby the image data D1 is efficiently encoded and output.

  Accordingly, the encoding unit 6C generates difference data D2 by motion compensation related to inter prediction and difference data D2 by intra prediction by inter coding and intra coding, respectively, and orthogonally transforms these difference data D2 by Quantization processing and variable length encoding processing are performed for transmission.

  The bit rate calculation unit 6A and the control unit 6B (FIG. 1) monitor the generated code amount by the encoding process by monitoring the free capacity of the storage buffer 21, and the quantization scale QP N in the quantization circuit 18 based on the monitoring result. Thus, the amount of generated code by the encoding unit 6C is controlled.

  That is, every time one picture is encoded, the bit rate calculation unit 6A detects the free capacity of the storage buffer 21, and thereby detects the generated code amounts Ik, Pk, and Bk of the I picture, P picture, and B picture. To do. Here, the generated code amounts Ik, Pk, and Bk are code amounts of the encoded data DF by each picture, and are code amounts including the index of each picture.

  The bit rate calculation unit 6A records and holds the generated code amounts Ik, Pk, and Bk detected from the accumulation buffer 21 by the number of pictures of each picture type constituting one GOP for each picture type constituting one GOP. Then, every time the generated code amount of one picture is detected, the oldest record among the corresponding generated code amount records recorded and held is updated with the detected code amount.

  In addition, the bit rate calculation unit 6A records and holds the latest code amounts Ik, Pk, and Bk by the number of pictures constituting one GOP as described above, and updates the recording of one picture each time. From these records, the code amounts BIT I, BIT P, and BIT B of each picture type in 1 GOP are obtained. As a result, the code amounts BIT I, BIT P, and BIT B of each picture type are recorded for each picture type as shown in the following formula. In total. Here, NUM I, NUM P, and NUM B are the number of pictures of each picture type constituting one GOP.

  Further, the bit rate calculation unit 6A calculates the generated code amount BIT GOP for 1 GOP by summing up the code amounts BIT I, BIT P and BIT B of these pictures as shown by the following equation.

  Further, the GOP average bit rate GOP RATE is calculated by dividing the generated code amount BIT GOP for 1 GOP by the duration GOP SEC of 1 GOP. Here, for example, when one GOP is composed of 15 pictures and the frame rate is 30 pictures / second, the duration GOP SEC of 1 GOP is 0.5 seconds obtained by dividing the number of pictures by the frame rate. Become. The bit rate calculation unit 6A notifies the control unit 6B and the display control unit 8 of the average bit rate GOP RATE.

  The control unit 6B determines the average bit rate GOP RATE notified in this way based on the upper limit bit rate RATE LIMIT instructed by the host controller 4, and determines the quantization scale QP N of the quantization circuit 18 based on the determination result. Control switching.

  That is, as shown by the following equation, when the average bit rate GOP RATE is smaller than the upper limit bit rate RATE LIMIT, the control unit 6B uses the quantization scale reference value QP INIT set according to the recording mode of the quantization circuit 18. Set to quantization scale QP N. Here, RATE CURRENT is an average bit rate GOP RATE.

  On the other hand, if this relationship does not hold, that is, if the average bit rate GOP RATE is greater than or equal to the upper limit bit rate RATE LIMIT, the quantum depends on the size of the average bit rate GOP RATE relative to the upper limit bit rate RATE LIMIT, as shown in the following equation. The quantization scale reference value QP INIT is corrected and set to the quantization scale QP N of the quantization circuit 18, and the bit rate of the encoded data DF output from the accumulation buffer 21 by the generated code amount temporarily increased thereby. The quantization scale QP N is corrected so as not to exceed the upper limit bit rate RATE LIMIT. Here, k is a coefficient for adjusting the response, and is set to a value of 1 in this embodiment.

  Here, in this digital video camera 1, three recording modes of LP mode, SP mode, and HQ (high quality) mode are prepared, and the control unit 6B is controlled by the host controller 4 in the LP mode, SP mode, and HQ mode. The upper limit bit rate RATE LIMIT is set to 6 [Mbps], 9 [Mbps] and 12 [Mbps], respectively, and the quantization scale reference value QP INIT is set to correspond to the upper limit bit rate RATE LIMIT. The

  Thus, in this embodiment, as shown in FIG. 3, the encoder 6 changes the bit rate according to the difficulty level of the image data D1 to be encoded according to the bit rate according to the recording mode, and encodes the encoded data DF. Is output. As described above, in the control unit 6B, the generated code amount that is temporarily increased by the average bit rate GOP RATE obtained from the generated code amount of each picture that has been most recently encoded as shown by the equation (3). If the quantized scale QP N is corrected so that the bit rate of the encoded data DF by does not exceed the upper limit bit rate RATE LIMIT, if this average bit rate GOP RATE rises higher than the upper limit bit rate RATE LIMIT The more it stands up, the rougher it is quantized, and the image quality will deteriorate accordingly. As a result, the average bit rate GOP RATE obtained from the amount of generated code of each picture that has been encoded recently can be said to represent the image quality after the encoding process, and is a parameter indicating the degree of image quality degradation. It can be said.

  As a result, the encoder 6 notifies the display control unit 8 of the parameters based on the average bit rate GOP RATE as image quality information.

  The recording / reproducing unit 7 switches the operation under the control of the host controller 4, records the encoded data DF output from the encoder 6 on the recording medium 2, and reproduces the encoded data DF recorded on the recording medium 2. Output to the playback data processing system. Here, the digital video camera 1 decodes the encoded data DF reproduced by the recording / reproducing unit 7 by a reproducing system (not shown) and displays the decoded data DF on the monitor unit 9.

  The recording medium 2 is various recording media such as a magnetic tape, an optical disk, and a memory card, for example. The recording / reproducing unit 7 records and holds the encoded data DF, and records and holds the encoded data DF. Output to the playback unit 7. As a result, the digital video camera 1 compresses the data obtained by the moving image acquired by the image capturing unit 5 by the encoder 6 and records it on the recording medium 2.

  The display unit 9 is a display unit that displays a monitor image of the imaging result captured by the imaging unit 5, and is configured by a liquid crystal display panel, for example. The display unit 9 is provided with a transparent touch panel on the display surface of the liquid crystal display panel, and notifies the host controller 4 of the operation of the touch panel.

  The host controller 4 is arithmetic processing means for controlling the operation of the digital video camera 1 and executes a program recorded in the memory by operating a touch panel provided on the display unit 9 and further by operating an operator (not shown). By doing so, the operation of each part is controlled. In this series of controls, the host controller 4 detects the selection of the menu displayed on the display unit 9 by operating the touch panel. When the selection of the recording mode is instructed by the selection of the menu, the recording mode according to this instruction is selected. The encoder 6 is notified of the upper limit bit rate RATE LIMIT and the quantization scale reference value QP INIT corresponding to. Thereby, the digital video camera 1 switches the recording mode of the imaging result to be recorded on the recording medium 2 in response to a user operation. Further, when the user instructs display on the image quality monitor by operating the touch panel, the host controller 4 switches the operation of the display control unit 8 and displays an analog amount display indicating the degree of image quality deterioration on the display unit 9 together with the monitor image. To do.

  That is, the display control unit 8 is a drive circuit that drives the display unit 9. The display control unit 8 drives the display unit 9 with the video signal S 1 output from the imaging unit 5, thereby displaying a monitor image of the imaging result on the display unit 9. .

  Further, the display control unit 8 causes the display unit 9 to display a display indicating the degree of image quality deterioration by the functional block of the bit rate graphic output unit 8A. In addition, the function block of the recording mode meter upper limit switching unit 8B displays a mark corresponding to the upper limit bit rate RATE LIMIT of the recording mode on the display indicating the degree of image quality deterioration. In addition, a menu for instructing switching of the recording mode is displayed on the display unit 9 so that the recording mode can be switched. Thereby, in the example shown in FIG. 1, the menus of the above-described HQ mode, SP mode, and LP mode are displayed.

  In this embodiment, the display indicating the degree of image quality deterioration is formed by displaying an analog amount corresponding to the average bit rate GOP RATE, which is a parameter indicating the degree of image quality deterioration. More specifically, the display of the analog rotation pointer type meter similar to a tachometer or the like in which the display position of the pointer is displaced so that the angle from the reference position becomes larger as the parameter value increases is displayed to indicate the degree of image quality deterioration. It is formed.

  That is, as shown in FIGS. 4A to 4C, in the display indicating the degree of image quality deterioration, a display area is formed by a circular shape, and the lower side of the area by the circular shape is directed from the circumference toward the center. The reference position corresponding to the generated code amount of 0 is displayed by the mark M1 of the line segment extending in this manner. Similarly, a mark M2 is arranged by a line segment extending toward the center at a position displaced by approximately 270 degrees in the clockwise direction from the reference position, and the generated code corresponding to the upper limit bit rate RATE LIMIT is arranged by this mark M2. The amount is indicated. Marks M3 and M4 are arranged at equal intervals between the mark M1 at the reference position and the mark M2 related to the upper limit bit rate RATE LIMIT.

  The display indicating the degree of image quality deterioration displays a pointer S whose center is a rotation axis in a circular area, and the direction from the reference position mark M1 to the mark M2 related to the upper limit bit rate RATE LIMIT. The display position of the pointer S is set so that the angle θ from the reference position mark M1 to the pointer S becomes a value corresponding to the parameter indicating the degree of image quality deterioration. Thus, an analog amount indicating the degree of image quality deterioration is set. An indication is formed. Thus, this angle θ (ANGLE CURRENT) is expressed by the following equation. Here, ANGLE BASE is an angle of the reference position, and ANGLE RANGE is an angle from the mark M1 of the reference position to the mark M2 related to the upper limit bit rate RATE LIMIT.

(2) Operation of Example In the above configuration, in this digital video camera 1 (FIGS. 1 and 2), the imaging result by the moving image obtained by the imaging unit 5 is input to the display control unit 8 by the video signal S1, and this The monitor image of the imaging result is displayed on the display unit 9 by driving the display unit 9 by the display control unit 8. The video signal S1 resulting from the imaging result is input to the encoder 6, where the data is compressed to generate encoded data DF, and the encoded data DF is recorded on the recording medium 2. As a result, in the digital video camera 1, a desired subject can be photographed and recorded on the recording medium 2 while confirming the imaging result with the monitor image displayed on the display unit 9.

  However, the monitor image displayed on the display unit 9 is based on the video signal S1 which is not compressed. On the other hand, the data compression process may deteriorate the image quality. In particular, in the case of a data compression method in which the amount of generated codes is limited to a certain amount, image quality degradation is significant in an image with intense motion. As a result, the image quality deterioration is not noticed until the image pickup result recorded on the recording medium 2 is reproduced at home or the like.

  Therefore, in this digital video camera 1, a parameter indicating the degree of image quality deterioration is detected by the encoder 6, and a display indicating the degree of image quality deterioration is formed on the monitor image by the display unit 9 by this parameter. As a result, the digital video camera 1 can easily check the image quality of the current recording mode during shooting without having to reproduce and check the imaging results recorded on the recording medium 2 one by one. A desired object can be photographed by selecting a recording mode.

  That is, in this digital video camera 1, in the encoder 6, the quantization scale QP N is varied by comparing the upper limit bit rate RATE LIMIT instructed by the host controller 4 as the control unit and the generated code amount of the encoded data DF. Thus, when the generated code amount of one picture output from the lossless encoding circuit 20 temporarily exceeds the limit by the upper limit bit rate RATE LIMIT, the subsequent picture is generated by changing the quantization scale QP N accordingly. Suppress the code amount. Thereby, in the digital video camera 1, the generated code amount is set in accordance with the degree of difficulty of encoding in the video signal S1 within a range where the bit rate of the encoded data DF output from the accumulation buffer 21 does not exceed the upper limit bit rate RATE LIMIT. The video signal S1 is subjected to data compression processing in a variable manner. Further, by switching the upper limit bit rate RATE LIMIT, the data compression rate of the encoded data DF is switched so as to correspond to the recording mode.

  Thus, in the digital video camera 1, when the generated code amount detected by the encoder 6 is a code amount corresponding to the upper limit bit rate RATE LIMIT, the upper limit bit rate RATE LIMIT is temporarily supported. When the amount of code exceeds the image quality, the image quality deteriorates. Further, when the amount of code that temporarily exceeds the code amount corresponding to the upper limit bit rate RATE LIMIT increases, the image quality deterioration correspondingly increases.

  Thus, in the digital video camera 1, the generated code amount of the encoded data DF is set as a parameter indicating the degree of image quality deterioration, and an analog amount corresponding to the parameter in which the mark M2 is set at a position corresponding to the upper limit bit rate RATE LIMIT. As a result, a display indicating the degree of image quality deterioration is formed (FIG. 4). Thereby, in the digital video camera 1, the degree of image quality deterioration can be grasped sensuously by comparing with the mark M2 at the position corresponding to the upper limit bit rate RATE LIMIT, and the user convenience is improved accordingly. Can do.

  Specifically, the encoder 6 detects the generated code amounts Ik, Pk, and Bk for each picture and varies the quantization scale QPN, and depends on the generated code amounts Ik, Pk, and Bk detected for each picture. The degree of image quality degradation is displayed by the parameter, and this ensures that the image quality degradation is notified to the user even when encoding is performed using VBR with the upper limit limited by the upper limit bit rate RATE LIMIT as in this embodiment. be able to.

  More specifically, the encoder 6 detects the generated code amount BIT GOP of 1 GOP from the generated code amounts Ik, Pk, and Bk detected for each picture, and the generated code amount BIT GOP of 1 GOP and the upper limit bit rate. The quantization scale QP N is varied by comparison with RATE LIMIT. In this way, a display indicating the degree of image quality deterioration is formed by the generated code amount BIT GOP of 1 GOP.

  Thus, in this embodiment, it is possible to form a display indicating the degree of image quality degradation by effectively using the parameters used for rate control of the encoder 6, and to improve the user-friendliness with a simple configuration. Can do.

  In the display of image quality deterioration, the mark M1 is displayed at the reference position where the generated code amount is 0, and the angle of the pointer from the reference position is increased according to the parameter indicating the degree of image quality deterioration. By changing the display position of the pointer and displaying it in the form of an analog rotary pointer type meter, it is possible to notify the user of the image quality deterioration sensuously and reliably notify the image quality deterioration.

(3) Advantages of the embodiment According to the configuration described above, the degree of image quality deterioration due to the data compression process is detected and displayed together with the monitor image, so that the image quality according to the current recording mode can be easily confirmed during shooting. Can do.

  In addition, by changing the quantization scale by comparing the upper limit bit rate instructed by the control unit and the generated code amount of the encoded data, the generated code amount can be set according to the video data within a range not exceeding the upper limit bit rate. By changing the upper limit bit rate, the data compression rate is changed so as to correspond to the recording mode, and the generated code amount is set as a parameter indicating the degree of image quality deterioration. By displaying the amount of degradation of the image by displaying the analog amount according to the parameter set with the mark at the position, the degree of degradation of the image quality can be grasped sensuously by comparing with the mark at the position corresponding to this upper limit bit rate. The user convenience can be improved accordingly.

  In addition, by detecting the generated code amount for each picture and changing the quantization scale, and setting the parameter indicating the degree of image quality deterioration by the generated code amount for each picture, the upper limit bit rate is set. Even when encoding processing is performed by limiting the upper limit value, it is possible to reliably notify the user of image quality deterioration.

  More specifically, the generated code amount is detected for each picture to detect the generated code amount of 1 GOP, and the quantization scale is varied by comparing the generated code amount of 1 GOP with the upper limit bit rate. By setting the generated code amount of 1 GOP as a parameter, it is possible to form a display indicating the degree of image quality degradation by effectively using the parameter used for rate control of the data compression process, and a simple display correspondingly. The user-friendliness can be improved by the configuration.

  Also, by changing the display position of the pointer so that the angle from the reference position where the generated code amount is 0 becomes large, the degree of image quality deterioration is displayed in the form of an analog rotary pointer meter, and this makes it possible to sense the image quality It is possible to notify the user of the deterioration and reliably notify the image quality deterioration.

  FIG. 5 is a plan view of a display showing the degree of image quality deterioration applied to the digital video camera according to Embodiment 2 of the present invention. The digital video camera according to this embodiment is configured in the same manner as the digital video camera 1 described above with reference to the first embodiment except that the display illustrated in FIG. 5 is applied instead of the display described above with reference to FIG. The

  That is, in this digital video camera 1, the degree of image quality deterioration is displayed by a bar display in which the length from the position where the generated code amount is 0 becomes longer as the parameter value increases. In addition, the upper limit of the variable range by the bar display is set to the code amount corresponding to the upper limit bit rate. In this case, the display described above for the first embodiment and the display shown in FIG. 5 may be switched in response to an operation by the user.

  According to this embodiment, the same effect as that of the first embodiment can be obtained even when the display of the analog amount indicating the degree of image quality deterioration is executed by the bar display in which the length from the reference position becomes longer due to the increase of the parameter value. be able to.

  FIG. 6 is a plan view of a display showing the degree of image quality deterioration applied to the digital video camera according to Embodiment 3 of the present invention. The digital video camera according to this embodiment is configured in the same manner as the digital video camera 1 described above with respect to the first embodiment except that the configuration relating to the display indicating the degree of image quality deterioration is different. Will be described using the configuration of FIGS. 1 and 2.

  Here, in this embodiment, the host controller 4 acquires the generated code amounts Ik, Pk, and Bk of the I picture, P picture, and B picture detected for each picture from the encoder 6, and the generated generated code amount. Ik, Pk, and Bk are converted into generated code amounts when the encoding process is performed using the reference value QP INIT of the quantization scale. In this conversion process, the quantization scale QP N subjected to the encoding process is divided by the reference value QP INIT of the quantization scale to obtain a coefficient, and the generated code amounts Ik, Pk, Bk are multiplied by this coefficient. Desired.

  Further, the host controller 4 calculates the generated code amount BIT GOP of 1 GOP by executing the arithmetic processing of the equations (1) and (2) based on the generated code amount converted in this way, and this generated generated code amount BIT GOP. To the display control unit 8 as a parameter indicating the degree of image quality degradation.

  The display control unit 8 displays a mark at a position corresponding to the upper limit bit rate RATE LIMIT of the LP mode, the SP mode, and the HQ mode, and displays the image quality by displaying the bar with the generated code amount BIT GOP notified from the host controller 4. Displays the degree of deterioration.

  Thus, in this embodiment, for example, when the imaging result is recorded in the SP mode, it is found that the image quality is deteriorated when the bar display exceeds the SP mode mark, and the amount exceeding the mark is large. It is shown that the degree of image quality deterioration is larger as the case is. On the contrary, it is possible to indicate that the recording is performed with an unnecessarily high image quality, and accordingly the recording mode can be set appropriately.

  According to this embodiment, by setting a mark at a position corresponding to the upper limit bit rate of each recording mode and displaying a bar indicating the degree of image quality deterioration, the user selects which recording mode by comparing each mark. It is possible to appropriately determine whether or not to do so, and accordingly, the usability can be further improved.

  FIG. 7 is a plan view showing the display of the display unit 9 applied to the digital video camera according to Embodiment 4 of the present invention. The digital video camera according to this embodiment is configured in the same manner as the digital video camera described above with reference to the first to third embodiments except that the configuration related to the display of the display unit 9 is different. 1 and FIG. 2 will be used for explanation.

  In this embodiment, a monitor image is displayed, and a bar display B1 indicating the degree of image quality degradation described above with respect to Embodiments 2 and 3 is formed on the display screen of the monitor image and in the lower right corner. Further, when the generated code amount detected by the parameter approaches the upper limit value related to the upper limit bit rate according to the current recording mode by a certain value or more, a text warning B2 is displayed. In this example of FIG. 7, although the warning B2 is formed by text indicating that the generated code amount has approached the upper limit value and the margin has decreased, the warning B2 is shown in FIG. As shown in FIG. 4, various symbols and marks that call attention to the user can be widely applied, and the bar display may be omitted and only such warnings may be displayed.

  According to this embodiment, it is possible to easily confirm the image quality according to the current recording mode during shooting by detecting the degree of image quality deterioration due to the data compression process and issuing a warning.

  In addition, since this warning is a warning via a display unit that displays a monitor image, it is possible to easily and reliably notify the user of image quality deterioration.

  In the digital video camera according to the present embodiment, in the configuration described above with respect to the third embodiment, the frequency and the size of the parameter indicating the degree of image quality deterioration exceeding the upper limit bit rate in the recording mode are tabulated, and the tabulated result is constant. The determination is made based on the determination reference value, whereby the current degree of image quality deterioration is determined based on the determination reference value. Further, based on the determination result, a message for instructing switching to the recording mode on the high image quality side is displayed on the display unit 9.

  In addition, the frequency and size at which the parameter indicating the degree of image quality degradation falls below the threshold corresponding to the upper limit bit rate of the recording mode with lower image quality than the current recording mode are aggregated, and this aggregated result is the same criterion value. Judgment by Further, based on the determination result, a message instructing switching to the recording mode on the low image quality side is displayed on the display unit 9. Here, the threshold value corresponding to the upper limit bit rate of the recording mode with low image quality is the quantization scale in the recording mode with low image quality relative to the reference value QP INIT of the quantization scale in the current recording mode. The generated code amount corresponding to the upper limit bit rate of the recording mode with low image quality is corrected and set by the reference value QP INIT.

  In this case, the recordable time based on the remaining capacity of the recording medium 2 when the recording mode is switched may be calculated and displayed. Further, the determination reference value and the threshold value for judging such a total result may be varied by setting by the user.

  As in this embodiment, by issuing a warning with a parameter indicating the degree of image quality degradation and setting this warning as an instruction to switch the recording mode, the user's usability can be further improved.

  In the above-described embodiment, the case where the degree of image quality deterioration is displayed simply by displaying an analog rotation pointer type meter or by bar display has been described, but the present invention is not limited to this, and colors are displayed on these displays. You may make it set. In this case, in the display of the analog rotation pointer type meter, the display portion corresponding to the dial plate or the display portion corresponding to the scale may be set to red within a range exceeding the upper limit bit rate. In the case of bar display, the bar display color may be switched from blue to red when the current upper limit bit rate is exceeded.

  In the above-described embodiments, the case where the degree of image quality deterioration is displayed based on the analog amount has been described. However, the present invention is not limited to this, and image quality deterioration is caused by selective lighting of marks such as red, blue, and yellow. You may make it display. In this case, for example, when the upper limit bit rate is approached, the yellow mark is lit, when the upper limit bit rate is exceeded, the red mark is lit, and in other cases, the blue mark is lit. Can be considered.

  In the above-described embodiment, the case where the image pickup result is compressed by the VBR method in which the generated code amount is limited by the upper limit bit rate has been described. However, the present invention is not limited to this, and the image pickup result is compressed by the CBR. It can be widely applied to cases.

  Further, in the above-described embodiments, the case where the present invention is applied to a digital video camera has been described. However, the present invention is not limited to this, and the present invention is widely applied to a case where an imaging result is acquired and recorded by various imaging devices. Can do.

  The present invention relates to a moving image recording apparatus and a moving image recording method, and can be applied to, for example, a digital video camera.

It is a block diagram which shows the digital video camera which concerns on Example 1 of this invention. FIG. 2 is a block diagram partially showing an encoder applied to the digital video camera of FIG. 1. It is a characteristic curve figure with which it uses for description of the encoding process in the digital video camera of FIG. FIG. 2 is a plan view of a display showing a degree of image quality deterioration in the digital video camera of FIG. 1. It is a top view of the display which shows the grade of image quality degradation in the digital video camera which concerns on Example 2 of this invention. It is a top view of the display which shows the grade of image quality degradation in the digital video camera which concerns on Example 3 of this invention. It is a top view of the display which shows the grade of image quality degradation in the digital video camera which concerns on Example 4 of this invention. It is a top view of the display which shows the grade of image quality degradation in the digital video camera concerning the other Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Digital video camera, 2 ... Recording medium, 4 ... Host controller, 5 ... Imaging part, 6 ... Encoder, 7 ... Recording / reproducing part, 8 ... Display control part, 9 ... Display part

Claims (5)

In a video recording apparatus that records a video on a recording medium, a video data acquisition unit that acquires a video data based on the video by photographing a subject;
A display unit for displaying a monitor image of a moving image by the video data acquired by the video data acquisition unit;
A data compression unit that performs data compression processing on the video data acquired by the video data acquisition unit and outputs encoded data;
A recording unit for recording the encoded data on the recording medium;
A control unit that switches a data compression rate of the data compression processing so as to correspond to the recording mode according to an instruction of the recording mode by a user;
A parameter detection unit that detects a parameter indicating the degree of deterioration of image quality due to the data compression processing,
The display unit
Based on the parameter, a display indicating the degree of deterioration of the image quality is displayed together with the monitor image,
The data compression unit
Generated according to the video data within a range not exceeding the upper limit bit rate by changing the quantization scale by comparing the upper limit bit rate instructed by the control unit and the generated code amount of the encoded data Variable code amount,
By switching the upper limit bit rate, the data compression rate is switched to correspond to the recording mode,
The display unit
The parameter is obtained from the generated code amount,
A mark is set at a position corresponding to the upper limit bit rate, and the degree of degradation of the image quality is displayed by displaying an analog amount according to the parameter,
The controller is
By selecting from multiple recording modes, the user accepts recording mode instructions,
The display unit
A moving picture recording apparatus that further sets and displays a mark at a position corresponding to the upper limit bit rate in another recording mode. The data compression unit
Detecting the amount of generated code for each picture and varying the quantization scale;
The moving image recording apparatus according to claim 1, wherein a generated code amount relating to the parameter is a generated code amount for each picture. The data compression unit
Detect the generated code amount for each picture,
The amount of generated code of 1 GOP is detected from the detection result,
By comparing the generated code amount of 1 GOP and the upper limit bit rate, the upper limit bit rate indicated by the control unit is compared with the generated code amount of the encoded data;
The moving image recording apparatus according to claim 1, wherein a generated code amount related to the parameter is a generated code amount of the 1 GOP.   The analog quantity display is
  This is a bar display that increases the length from the reference position due to the increase in the parameter.
  The moving image recording apparatus according to claim 1.   In a video recording method for recording a video on a recording medium
  A video data acquisition step of capturing a subject and acquiring video data of the video;
  A display step of displaying a monitor image of a moving image by the video data acquired in the video data acquisition step;
  A data compression step of performing data compression processing on the video data acquired in the video data acquisition step and outputting encoded data;
  A recording step of recording the encoded data on the recording medium;
  A control step of switching a data compression rate of the data compression processing so as to correspond to the recording mode according to an instruction of the recording mode by the user;
  A parameter detection step of detecting a parameter indicating a degree of deterioration of image quality due to the data compression processing,
  In the display step,
  Based on the parameter, a display indicating the degree of deterioration of the image quality is displayed together with the monitor image,
  In the data compression step,
  By varying the quantization scale by comparing the upper limit bit rate instructed in the control step and the generated code amount of the encoded data, the video data can be set within a range not exceeding the upper limit bit rate. Variable the amount of generated code,
  By switching the upper limit bit rate, the data compression rate is switched to correspond to the recording mode,
  In the display step,
  The parameter is obtained from the generated code amount,
  A mark is set at a position corresponding to the upper limit bit rate, and the degree of degradation of the image quality is displayed by displaying an analog amount according to the parameter,
  In the control step,
  By selecting from multiple recording modes, the user accepts recording mode instructions,
  In the display step,
  A mark is further set and displayed at a position corresponding to the upper limit bit rate in other recording modes.
  Video recording method.

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