JP2010178124A - Recording apparatus and recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording technology for effectively reproducing sound when an image is reproduced in slow motion at the time of normal reproducing. <P>SOLUTION: A video camera 100 is provided with a recording and reproducing control section 9 which records on a recording medium 11 video data acquired at a second frame rate higher than a first frame rate, and extends sound data acquired for the video data of the first frame rate on a time axis based on a ratio of the second frame rate to the first frame rate by using a predetermined speech speed conversion technique and records it on the recording medium 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a recording apparatus and a recording method for recording moving image data and sound data on a recording medium.

  In recent years, with the advancement of technology for recording moving image data, an apparatus that realizes shooting and recording at a high frame rate (hereinafter simply referred to as “recording”) has started to appear. For example, moving picture data is higher than a conventional frame rate of 60 frames per second (hereinafter also referred to as “first frame rate”), for example, a frame rate of 300 frames per second (hereinafter also referred to as “second frame rate”). ), And recording devices such as video cameras and digital cameras that record on a recording medium have been commercialized.

  By capturing moving image data at a high speed at the second frame rate and playing it back at the first frame rate, for example, high-speed movements such as drops of water drops on the liquid surface and flapping of birds flutter smoothly. Can be played. When the second frame rate is 300 fps and the first frame rate is 60 fps, 1 / 5-times slow motion playback is performed.

Japanese Patent Laid-Open No. 2008-153795

  However, in slow motion reproduction by such a recording apparatus, generally no sound is reproduced. This is because the length of time changes between when a moving image is recorded and when it is played back, and even if sound is recorded at the same time, it does not match the reproduced moving image in time. For example, assume that moving image data is recorded for 1 second at 300 frames per second, and sound is also recorded during that time. When this is played back at 60 frames per second, the video is played back in slow motion for 5 seconds, but there is only one second of sound, and a fundamental problem arises in simultaneous playback of moving images and sounds. For this reason, recording of moving image data for slow motion playback is generally abandoned, and there is a problem that the realism is inevitably lacking compared to normal moving image playback with sound. there were.

  The present invention has been made in view of these problems, and an object thereof is to provide a recording technique in which sound is effectively reproduced even in the slow motion reproduction as described above. Another object of the present invention is to provide a recording technique in which sound is effectively played back when a video is in slow motion playback during normal playback, even if there is no special mechanism in the device that plays back moving images and sounds. is there.

  In order to solve the above problems and achieve the above object, a recording apparatus of the present invention includes a moving image recording control unit that records moving image data acquired at a second frame rate higher than the first frame rate on a recording medium, The sound data acquired corresponding to the moving image data at the first frame rate is converted into time using a predetermined speech rate conversion technique based on a ratio of the second frame rate to the first frame rate. A sound recording control unit that extends on the shaft and records the information on the recording medium.

  The recording method of the present invention corresponds to the moving image recording control step of recording moving image data acquired at a second frame rate higher than the first frame rate on a recording medium, and the moving image data at the first frame rate. Recording the sound data acquired on the recording medium by extending the sound data on the time axis using a predetermined speech speed conversion technique based on the ratio of the second frame rate to the first frame rate Control steps.

  According to the present invention, it is possible to provide a recording technique in which sound is effectively reproduced even in slow motion reproduction. In addition, according to the present invention, it is possible to provide a recording technique in which sound is effectively reproduced in slow motion reproduction without a special mechanism in a device that reproduces moving images and sounds. That is, the playback device does not need to have a slow motion playback function, and when the playback is normally performed on such a playback device, the moving image is played back in slow motion. Reproduced and a sense of realism appears.

3 is a functional block diagram illustrating a configuration of a video camera according to Embodiment 1. FIG. It is a flowchart which shows each step of the operation | movement which a video camera records moving image data and sound data. It is a figure which shows the method of extending LPCM data acquired by the sampling rate of 48 KHz and 16-bit sampling 5 times. FIG. 10 is a diagram for describing an operation of generating a stream by multiplexing moving image data and sound data in the third embodiment. FIG. 20 is a diagram for describing an operation of generating a stream by multiplexing moving image data and sound data in the fourth embodiment. It is a figure for demonstrating the priority at the time of reproduction | regeneration of the sound data of an uncompressed sound format, and the sound data of a compressed sound format.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to drawings. In the following description, the recording apparatus of the present invention will be described taking a video camera as an example.

(Embodiment 1)
First, the configuration of the video camera 100 of Embodiment 1 will be described with reference to FIG. FIG. 1 is a functional block diagram showing the configuration of the video camera 100 according to the first embodiment.

  As shown in FIG. 1, the video camera 100 according to the first embodiment includes a recording device 101 that performs recording processing of moving image data and sound data, and a reproducing device 102 that performs reproduction processing of moving image data and sound data.

  The recording apparatus 101 includes an optical unit 1, an imaging unit 2, a moving image A / D conversion unit 3, a data management unit 4, a first random access memory (RAM) 5, a signal switching unit 6, and a microphone. 7, a sound A / D converter 8, a recording / playback controller 9, a second RAM 10, and a recording medium 11.

  The optical unit 1 is a unit that collects light, the imaging unit 2 is a unit that converts light into an electric signal, and the moving image A / D conversion unit 3 is a unit that converts an analog signal into a digital signal. The data management unit 4 is a unit for managing data obtained by the moving image A / D conversion unit 3, the first RAM 5 is a unit for holding data, and the signal switching unit 6 is a unit for controlling the destination of data. It is. The microphone 7 is means for collecting sound and converting it into an electrical signal, and the sound A / D converter 8 is means for converting an analog signal into a digital signal. The recording / reproducing control unit 9 is means for controlling data recording and reproduction, the second RAM 10 is means for holding data, and the recording medium 11 is means for recording data.

  The playback device 102 includes a signal switching unit 6, a recording / playback control unit 9, a recording medium 11, a moving image D / A conversion unit 12, a display unit 13, a sound D / A conversion unit 14, and a speaker 15. And have.

  The signal switching unit 6, the recording / playback control unit 9, and the recording medium 11 are the above-described means and are included in the recording device 101 and the playback device 102. The moving image D / A conversion unit 12 is a unit that converts a digital signal into an analog signal, and the display unit 13 is a unit that displays an image. The sound D / A converter 14 is a means for converting a digital signal into an analog signal, and the speaker 15 is a means for outputting sound.

  Note that the video camera 100 also includes an operation unit 16 that is operated by a user and receives a user instruction.

  Next, the operation of the video camera 100 of Embodiment 1 will be described. Since the operation of the video camera 100 includes an operation of recording moving image data and sound data and an operation of reproducing the recorded moving image data and sound data, these operations will be described in order.

  First, the operation when the video camera 100 records moving image data will be described with reference to FIG. FIG. 2 is a flowchart showing each step of the operation when the video camera 100 records moving image data.

  The optical unit 1 collects the light that is the source of the image to generate an optical image of the subject, and the imaging unit 2 converts the generated optical image into an electrical signal. The moving image A / D conversion unit 3 converts the analog signal obtained by the imaging unit 2 into a digital signal, thereby generating digital moving image data (S1).

  When the user performs an operation for recording moving image data at a normal frame rate, for example, 60 fps, on the operation unit 16, the data management unit 4 displays the moving image data obtained by the moving image A / D conversion unit 3. Is output to the signal switching unit 6. The signal switching unit 6 outputs the moving image data from the data management unit 4 to the recording / playback control unit 9. The recording / playback control unit 9 records the moving image data from the signal switching unit 6 on the recording medium 11 at a normal frame rate.

  By the way, when the recording target image is a high-definition image, the data of the recording target image is recorded on the recording medium 11 with a resolution of 1920 pixels × 1080 pixels and a frame rate of 60 fps. In that case, the signal switching unit 6 sends data of 60 images per second to the recording / reproducing control unit 9.

  In recent years, a Complementary Metal Oxide Semiconductor (CMOS) sensor that can generate moving image data at a frame rate of 300 fps, which is 5 times as high as 60 fps, has been put to practical use as the imaging unit 2.

  Therefore, the user can instruct the operation unit 16 to record moving image data at a frame rate that is five times the normal rate, for example, at 300 fps. When moving image data is processed by the recording / playback control unit 9 at a frame rate of 300 fps, the signal switching unit 6 sends the moving image data to the recording / playback control unit 9 at a speed five times that of 60 fps, and transmission corresponding to the speed. Bandwidth is required.

  In consideration of the case where it is difficult to secure the transmission band, in Embodiment 1, when the moving image data is processed by the recording / playback control unit 9 at a frame rate of 300 fps, the data management unit 4 The moving image data generated by the / D conversion unit 3 is temporarily stored in the first RAM 5. After the storage process is completed, the data management unit 4 sends the moving image data temporarily stored in the first RAM 5 to the recording / playback control unit 9 via the signal switching unit 6. The recording / reproducing control unit 9 records the moving image data from the signal switching unit 6, that is, the temporarily accumulated moving image data on the recording medium 11.

  When moving image data is temporarily stored in the first RAM 5, the time during which a moving image can be shot at 300 fps is limited by the capacity of the first RAM 5. However, in recent years, it has become possible for consumer video cameras to capture and store moving image data having an image size of 720 pixels × 480 pixels at 300 fps for about 4 seconds. Since 300 fps is 5 times the speed of 60 fps, when the accumulated moving image data is reproduced at a normal speed of 60 fps, a moving image of 20 seconds is reproduced.

  60 fps is an example of the first frame rate, and 300 fps is an example of the second frame rate. Hereinafter, a case where moving image data is recorded on the recording medium 11 at the second frame rate of 300 fps will be described.

  When the moving image data is recorded on the recording medium 11 at the second frame rate of 300 fps, the data management unit 4 stores the moving image data generated at 300 fps by the imaging unit 2 and the moving image A / D conversion unit 3 up to 4 times. Temporarily accumulates in the first RAM 5 for up to a second (S2). Thereafter, the data management unit 4 sends the moving image data temporarily stored in the first RAM 5 to the recording / reproduction control unit 9 at 60 fps via the signal switching unit 6. Since the moving image data is sent to the recording / playback control unit 9 at 60 fps, the recording / playback control unit 9 processes the moving image data temporarily stored in the first RAM 5 at 60 fps, which is the same as in normal shooting.

  When the moving image data is data of an image having an image size of 720 pixels × 480 pixels, the data management unit 4 resizes the image of 720 pixels × 480 pixels, and then adds a black frame around the image, thereby 1920 An image of pixels × 1080 pixels is generated, and moving image data corresponding to the generated image is sent to the recording / playback control unit 9.

  How much the image of 720 pixels × 480 pixels is enlarged by resizing is determined by how much degradation of image quality is allowed. If it is allowed to enlarge the original image up to 2 times, the resized image is an image of 1440 pixels × 960 pixels, and each image of the moving image data sent to the recording / playback control unit 9 is 1440 pixels × 960. An image of 1920 × 1080 pixels with a black frame around the pixel image is obtained.

  As described above, the moving image data temporarily stored in the first RAM 5 at a speed of 300 fps is sent to the recording / playback control unit 9 at a speed of 60 fps after the temporary storage process is completed. A video stream is generated as a high-definition image by an internal video encoder in the Advanced Video Code High Definition (AVCHD) format (S3).

  The recording / playback control unit 9 includes a moving image encoder and a moving image decoder that can compress high-definition images in the AVCHD format. The video decoder operates during playback.

  Next, an operation when the video camera 100 reproduces moving image data will be described.

  The recording / playback control unit 9 acquires the moving image data from the recording medium 11 and reproduces it, the moving image D / A conversion unit 12 converts the reproduced digital moving image data into analog moving image data, and the display unit 13 Then, an image based on the analog moving image data generated by the moving image D / A converter 12 is displayed.

  Incidentally, since moving image data shot at 300 fps has a time length five times that of 60 fps, it takes five times the shooting time to encode and record the data on the recording medium 11. Then, when the recorded stream is reproduced at a normal speed of 60 fps, a 1 / 5-times slow motion video is reproduced.

  Next, the operation when the video camera 100 records sound will be described with reference to FIG. FIG. 2 is also a flowchart showing each step of the operation when the video camera 100 records sound data.

  The microphone 7 collects sound and converts it into an electric signal, and the sound A / D converter 8 converts the analog electric signal into a digital electric signal, thereby generating digital sound data (S4). The sound A / D conversion unit 8 sends the generated sound data to the recording / playback control unit 9. The sound A / D converter 8 samples the sound at 48 KHz, which is the same as when the moving image is recorded at the normal recording speed of 60 fps, even during the period when the moving image is captured at 300 fps.

  While the moving image data is stored in the first RAM 5, the recording / playback control unit 9 temporarily stores the sound data generated by the sound A / D conversion unit 8 in the second RAM 10 (S5).

  The recording / reproducing control unit 9 temporarily stores the moving image data generated at 300 fps by the imaging unit 2 and the moving image A / D conversion unit 3 in the first RAM 5 for a maximum of 4 seconds, Are obtained from the RAM 10 and processed (S6), and a sound stream is generated.

  Next, processing of sound data performed by the recording / playback control unit 9 will be described.

  When a moving image is shot at 300 fps for 4 seconds and the moving image is played back at 60 fps, the playback time is 5 times 4 seconds, which is 20 seconds. However, the sound data stored in the second RAM 10 is sound data for 4 seconds. Therefore, the recording / playback control unit 9 extends the sound data five times on the time axis. Here, even if the sound data is simply copied four times for each sample and the data amount is increased by five times, the sound data is extended by five times on the time axis. Is reduced to 1/5, and it is difficult to put it into practical use in terms of hearing.

  Therefore, even if the data amount is extended five times on the time axis during recording, a process is performed in which the frequency does not decrease during reproduction. That is, the recording / playback control unit 9 generates sound data corresponding to the moving image data having the first frame rate of 60 fps for each predetermined unit based on the ratio of the second frame rate of 300 fps to the first frame rate. The sound data is processed a plurality of times (S6). Then, the recording / playback control unit 9 performs encoding for converting the processed sound data into a sound stream (S7), multiplexes the moving image stream and the sound stream (S8), and records the multiplexed stream on the recording medium 11. (S9).

  When the sound data is repeated a plurality of times for each predetermined unit, the recording / playback control unit 9 repeats the sound data for each predetermined unit the number of times obtained by dividing the second frame rate by the first frame rate. In the example described above, since the first frame rate is 60 fps and the second frame rate is 300 fps, the recording / playback control unit 9 repeats the sound data five times for each predetermined unit. Details of the process in which the recording / playback control unit 9 repeats sound data of a predetermined unit will be described later with reference to FIG.

  Note that the recording / playback control unit 9 may, for example, use a known speech speed conversion technique or sound playback speed conversion in order to make the pitch almost the same as the case where the sound data is not stretched even if it is stretched five times. Use technology.

  Next, as one embodiment of the speech speed conversion, a method of reducing the processing load of the sound data in the recording / playback control unit 9 although it is inferior in sound quality will be described with reference to FIG.

  FIG. 3 is a diagram illustrating a method of extending Linear Pulse Code Modulation (LPCM) data acquired by the microphone 7 at a sampling rate of 48 KHz and 16-bit sampling by five times. LPCM is one of the methods for converting an analog signal such as sound into a digital signal, and is a method in which data is not compressed. That is, LPCM data is uncompressed data. 3 shows the case where the sound data is only one channel for simplification of explanation, the method shown in FIG. 3 is a case where the sound data is data of a plurality of channels such as stereo. But it is applicable.

  FIG. 3A shows LPCM data acquired by the microphone 7 and the sound A / D converter 8 at a sampling rate of 48 KHz and 16-bit sampling.

  FIG. 3B shows 800 samples which are unit data taken out by the recording / playback control unit 9 from the beginning of the data of the LPCM of FIG.

  FIG. 3C shows data in which the 800 samples in FIG. 3B are copied by the recording / playback control unit 9, and then the leading portion of the 800 samples is faded in and the trailing portion is faded out.

  Next, fade-in processing and fade-out processing performed by the recording / playback control unit 9 will be described.

  First, the fade-in process will be described.

  The recording / playback control unit 9 performs a fade-in process based on the following equation (1).

Output = Input × x / w (1)
Here, Output is the result, Input is the original data, x is the position of the sample, and w is the number of samples to be faded in (in this case, 100). The position x of the sample at which the fade-in process is started is “0”.

  Next, the fade-out process will be described.

  The recording / playback control unit 9 performs a fade-out process based on the following equation (2).

Output = Input × (100 × x) / w (2)
Here, Output is the result, Input is the original data, x is the position of the sample, and w is the number of samples to be faded in (in this case, 100). Note that the position x of the sample at which the fade-out process starts is “0”.

  In FIG. 3D, the data in which the head portion shown in FIG. 3C is faded in and the tail portion is faded out is added five times while being recorded 100 samples at a time by the recording / playback controller 9. The state is shown. Thereby, the recording / reproducing control unit 9 generates LPCM data obtained by extending the original data by five times.

  FIG. 3E shows LPCM data obtained by extending the original data by 5 times by the recording / playback control unit 9. In FIG. 3E, a portion surrounded by an ellipse is a portion where the fade-in processed data is added to the fade-out processed data.

  If the data shown in FIG. 3B is simply repeated five times and connected without doing this, the waveform of the coupling part becomes discontinuous, and impulse noise is generated for hearing during reproduction. Generation of impulse noise can be prevented by adding the result of the fade-in process and the result of the fade-out process.

  The recording / playback control unit 9 connects 700 units of the unit data immediately before the start of connection (see FIG. 3A) when connecting the extended unit data to the next unit data. Start the concatenation process from the advanced position.

  In this way, the recording / playback control unit 9 extends LPCM data while preventing the generation of impulse noise, and generates sound data that is played back slowly without changing the pitch during playback.

  Note that the way in which sound is heard varies greatly depending on how the number of samples of unit data to be subjected to fade-in and fade-out processing shown in FIG. 3B is selected. For example, in the case of a sound of “good morning”, if the number of unit data samples is small, it sounds like “Oh, oh, hahahaha…” and there are many unit data samples. , "Good morning, good morning, good morning." The number of unit data samples depends on the sampling rate, but when the sampling rate is 48 kHz, the number of unit data samples seems to be about 800 samples.

  Also, the sound data processing for extending the sound data on the time axis is not limited to the example described with reference to FIG. However, since the target sound is not limited to a human conversation, it is inappropriate to perform a process of detecting a silent section and filling it in time.

  Next, an operation when the video camera 100 reproduces sound data will be described.

  The recording / reproducing control unit 9 acquires sound data from the recording medium 11 and reproduces the sound data at a normal speed corresponding to 60 fps, which is a normal frame rate (first frame rate), and the sound D / A conversion unit 14 Converts the reproduced digital sound data into analog sound data, and the speaker 15 outputs a sound based on the sound data obtained by the sound D / A converter 14.

  As described above, in the first embodiment, the recording / playback control unit 9 performs the processing for extending the sound data before recording the sound data on the recording medium 11 (see S6 in FIG. 2 and FIG. 3). Thus, when the recording / playback control unit 9 plays back moving image data recorded on the recording medium 11 at a high-speed second frame rate of 300 fps at a normal frame rate (first frame rate) of 60 fps, 1 A smooth slow-motion image with a speed of 5 times is played, and at the same time, a sound with a sense of presence that does not change the pitch so much.

  Further, since the recording / reproducing control unit 9 performs a process of extending the sound data before recording the sound data on the recording medium 11, no special device for reproducing the sound data is required. The stream recorded on the recording medium 11 is not different from that normally recorded as a format, and the reproducing apparatus can reproduce the stream recorded on the recording medium 11 in the same manner as the normally recorded stream. In addition, the realistic sound of slow motion video is played back in slow motion.

(Embodiment 2)
In the first embodiment, the sound data to be processed is once sent to the recording / playback control unit 9 at the time of shooting an image and temporarily stored in the second RAM 10. In the second embodiment, the sound data to be processed is Is stored in the first RAM 5 together with the moving image data when the image is taken. That is, the sound data to be processed is temporarily stored in the second RAM 10 before being processed by the recording / playback control unit 9 in the first embodiment, but in the second embodiment, the recording / playback control unit 9 is used. Is temporarily stored in the first RAM 5 before being processed. This is the difference between the first embodiment and the second embodiment.

  Note that when moving image data and sound data are sent from the first RAM 5 to the recording / playback control unit 9, a stream in which the moving image data is encoded and a stream in which the sound data is encoded can be multiplexed at a speed. The moving image data and the sound data are supplied from the first RAM 5 to the recording / reproducing control unit 9.

(Embodiment 3)
In the third embodiment, the case where the AVCHD encoder of the recording / playback control unit 9 has the ability to encode at 5 × speed if the data to be processed is standard definition (SD) data will be described with reference to FIG. . FIG. 4 is a diagram for explaining an operation of generating a stream by multiplexing moving image data and sound data in the third embodiment. If the encoder is compatible with high-definition (HD), it is possible to sufficiently encode SD data at 5 × speed. Further, the encoder according to the third embodiment can process data at a double speed of 120 fps or a quadruple speed of 240 fps if the speed is 5 times or less.

  The imaging unit 2 generates moving image data at an image size of 720 pixels × 480 pixels at a speed of 300 fps, and the generated moving image data is supplied to the recording / playback control unit 9 through the signal switching unit 6. The recording / playback control unit 9 assumes that the SD moving image data is supplied at a normal 5 times speed of 60 fps, and processes the data to be processed at a real time speed of 5 times to generate an image stream. In this case, a bandwidth five times that for processing an SD image is required, but a high-definition image is an image of 1920 pixels × 1080 pixels, and has a pixel amount six times that of an SD image. Therefore, an encoder that supports high-definition signals can sufficiently encode SD images at 5 times speed, depending on the implementation.

  Since the recording / playback control unit 9 encodes the data to be processed by AVCHD at 5 times the real time, the encoded data is recorded on the recording medium 11 even if the bit rate of the data to be processed is 4 Mbps. The bit rate at that time is 5 times 20 Mbps. When the recording medium 11 is a hard disk and the recordable bit rate exceeds 50 Mbps, no problem occurs in the recording process even if the bit rate of the recorded SD stream is a little higher. However, if the recording medium 11 is a medium that causes problems when recording when the recording bit rate exceeds about 25 Mbps to 30 Mbps, such as a memory card, the bit rate of the encoded SD stream should be suppressed to 5 Mbps or less. . Nevertheless, if SD data is encoded by AVCHD, a sufficiently high-quality image can be obtained even at 5 Mbps, so no problem occurs.

  So far, the image processing has been described. Next, sound processing will be described. An object of the present invention is to record realistic sound data suitable for an image when moving image data is reproduced in slow motion. A method for processing sound data so that when a recorded AVCHD stream is normally played back, the sound is played back at a speed of 1/5 and the pitch does not change much will be described.

  Sound is input from the microphone 7 to the recording / playback control unit 9 through the sound A / D conversion unit 8 while shooting a moving image at 5 × speed. The sound data is input to the recording / playback control unit 9. The recording / playback control unit 9 first extends the sound data by 5 times by the method described in the first embodiment, encodes the sound data at 5 times speed by the AC3 encoder, and generates a stream at a 5 times bit rate.

  The recording / playback control unit 9 also multiplexes the image stream and the sound stream at 5 × speed. As a result, when the image is normally reproduced, the image is reproduced in a slow motion of 1/5, and the sound corresponding to the sound is generated, and an SD AVCHD standard stream reproduced in a realistic state is generated.

  In Embodiment 3, the video camera 100 encodes (compresses) images and sounds while shooting at a high speed such as 300 fps, and records a stream obtained by encoding on the recording medium 11. This is the fundamental difference between the third embodiment and the first and second embodiments.

  The video camera 100 according to the third embodiment has the following advantages (i) and (ii) over the video camera 100 according to the first and second embodiments.

  (I) Shooting can be continued as long as the recording medium 11 has free space without being limited by the first RAM 5.

  (Ii) The video camera 100 according to the first and second embodiments requires “the time of shooting + n times the time (n depends on the speed of high-speed shooting)” as the time required for shooting and recording. And If 30 seconds is taken at 300 fps and n is “5”, the video camera 100 of Embodiments 1 and 2 has “30 seconds + 30 seconds × 5” as the time required for shooting and recording, that is, “ 180 seconds "is required. On the other hand, the video camera 100 according to Embodiment 3 can perform shooting and recording in real time (30 seconds).

(Embodiment 4)
In the third embodiment, the recording / playback control unit 9 encodes the sound data with AC3. This is because the AVCHD standard requires that the sound data be encoded with AC3, but depending on the system configuration, the AC3 may not be encoded at 5 × speed. An alternative means in that case will be described with reference to FIG. FIG. 5 is a diagram for explaining an operation of generating a stream by multiplexing moving image data and sound data in the fourth embodiment.

  According to the AVCHD standard, it is also permitted to record sound data in LPCM. Even in such a case, AC3 sound data is essential, and the recording / playback control unit 9 generates silence data in AC3 and records the sound data extended five times by LPCM. Thereby, the recording / reproducing control unit 9 can add the target sound data to the moving image stream in a state where the AVCHD standard is satisfied.

  When playing the stream, the playback device seems to select AC3 sound data by default. In that case, the sound is silent during reproduction as it is, but when the user operates the reproduction device to select sound data of LPCM, the target sound is reproduced.

  Even when it is difficult to move the AC3 encoder at 5 × speed, it is considered that the process of generating AC3 silence data and generating a stream is often possible using a part of the AC3 encoder. The configuration of the fourth embodiment is effective as an alternative means when the configuration of the third embodiment cannot be realized.

(Embodiment 5)
Sound data is often recorded at a sampling frequency of 48 KHz and a quantization bit number of 16 bits. This is for reproducing high-quality sound, but depending on the configuration of the system to which the present invention is applied, there may be cases where the processing load is too heavy to deal with. In that case, for example, if the sampling frequency is set to 24 KHz, the amount of data to be processed is reduced by half, so that the system may be able to process.

  In addition, when the number of quantization bits is 16 bits as the accuracy of the calculation, the processing load is heavy and this cannot be dealt with.

  Although the sound quality deteriorates when one or both of the sampling frequency and the number of quantization bits are lowered, the sound data is processed in accordance with the slow motion image, and the normal sampling frequency 48 KHz, quantum If the sound quality is within the practical range even if the sound quality is lower than the 16-bit sound, dropping the sampling frequency and / or the quantization bit number will not impair the merchantability. .

  If the sound to be processed is originally a 2ch stereo sound, the 2ch is mixed into a monaural sound, then processed as a 1ch monaural sound, and 2ch (L By returning to the same sound as R and R, the amount of processing for extending the sound data on the time axis with a large load can be halved. Also by this, it seems that merchantability is not impaired for the same reason as described above.

  Therefore, the recording / playback control unit 9 reduces the sampling frequency of the sound data to be processed, reduces the number of quantization bits of the sound data to be processed, and the sound data when the sound data is a stereo signal. The amount of sound data to be processed may be reduced by executing all or part of the conversion to a monaural signal. Thereby, the processing load of the recording / reproducing control unit 9 is reduced.

(Embodiment 6)
In the sixth embodiment, the recording / playback control unit 9 records dummy silence in AC3 and records sound data subjected to the processing of the present invention in LPCM, and the stream is recorded on an AVCHD disc (DVD). In order to reproduce the LPCM sound data, which is the sound data of the uncompressed sound format, prior to the AC3 dummy silent sound data, which is the sound data of the compressed sound format, at the time of writing and reproduction, the following processing is performed. Do.

  That is, the recording / playback control unit 9 gives priority to the identification number of LPCM sound data that is sound data in uncompressed sound format over the identification number of AC3 dummy silent sound data that is sound data in compressed sound format. Recording is performed on the recording medium 11.

  For example, as shown in FIG. 6, the recording / playback control unit 9 sets the LPCM sound data identification number, which is sound data in the uncompressed sound format, to “1”, and a dummy silence of AC3, which is the sound data in the compressed sound format. The sound data identification number is set to “2”, and information for specifying the priority order is recorded on the recording medium 11. It is assumed that the lower the identification number, the higher the priority. In this case, when sound data is reproduced by an AVCHD-compatible player and recorder, it can be expected that LPCM sound data is preferentially reproduced.

  That is, the playback apparatus includes a moving image playback control unit that plays back moving image data recorded on a recording medium, an LPCM sound data identification number that is sound data in an uncompressed sound format recorded on the recording medium, and a compressed sound. A sound reproduction control unit that compares the identification number of the AC3 dummy silent sound data that is the format sound data and reproduces the sound data having the identification number having a high priority may be provided.

  In the above-described process, when the start of the Play List STN Table Audio stream specified in the AVCHD standard is set to LPCM and the next entry is set to Dolby Digital, a general player and recorder are found first. Do this because it seems to play sounds by default.

  The AVCHD standard does not specify which of the AC3 sound data and the LPCM sound data should be played by default, so although it is not certain, the above-described processing can be expected to be feasible in many cases. . If this is not the case, if the user selects LPCM sound data by remote control operation or the like, the target sound is reproduced. For example, the user is allowed to select the identification number “1”.

  That is, the playback apparatus includes a moving image playback control unit that plays back moving image data recorded on a recording medium, an LPCM sound data identification number that is sound data in an uncompressed sound format recorded on the recording medium, and a compressed sound. A sound reproduction control unit that reproduces sound data to which the identification number selected by the user among the identification numbers of the AC3 dummy silent sound data that is the format sound data may be provided.

  An example of an embodiment of the recording apparatus of the present invention is a video camera and a digital camera.

  The recording / playback control unit 9 in the above-described embodiment is an example of a moving image recording control unit and a sound recording control unit of the recording apparatus of the present invention.

  In addition, the moving image may be encoded and recorded on the recording medium 11 according to a standard such as Moving Picture Expert Group (MPEG). The standard for encoding the moving image may be any standard.

  Further, the recording medium 11 may be a removable medium that is not provided in the video camera 100.

DESCRIPTION OF SYMBOLS 100 Video camera, 101 Recording apparatus, 102 Playback apparatus, 1 Optical part, 2 Imaging part, 3 A / D conversion part for moving images, 4 Data management part, 5 1st RAM, 6 Signal switching part, 7 Microphone, 8 Sound A / D conversion unit, 9 recording / playback control unit, 10 second RAM, 11 recording medium, 12 moving image D / A conversion unit, 13 display unit, 14 sound D / A conversion unit, 15 speaker, 16 operation Department.

Claims (7)

A moving image recording control unit for recording moving image data acquired at a second frame rate higher than the first frame rate on a recording medium;
The sound data acquired corresponding to the moving image data at the first frame rate is converted into time using a predetermined speech rate conversion technique based on a ratio of the second frame rate to the first frame rate. A sound recording control unit that extends on a shaft and records the sound on the recording medium. The sound recording control unit records silence data in the compressed sound format on the recording medium, and converts the sound data to a predetermined speech speed conversion based on a ratio of the second frame rate to the first frame rate. The recording apparatus according to claim 1, wherein the recording apparatus is stretched on a time axis using a technique and recorded on the recording medium in an uncompressed sound format. The recording apparatus according to claim 2, wherein the sound recording control unit records the identification number of the sound data in the uncompressed sound format on the recording medium in preference to the identification number of the sound data in the compressed sound format. The sound recording control unit lowers the sampling frequency of the sound data, reduces the number of quantization bits of the sound data, and converts the sound data when the sound data is a stereo signal into a monaural signal. The recording apparatus according to claim 1, wherein all or part of the conversion is performed. A moving image recording control step of recording moving image data acquired at a second frame rate higher than the first frame rate on a recording medium;
The sound data acquired corresponding to the moving image data at the first frame rate is converted into time using a predetermined speech rate conversion technique based on a ratio of the second frame rate to the first frame rate. And a sound recording control step of recording on the recording medium by stretching on an axis. In the sound recording control step, silence data is recorded on the recording medium in a compressed sound format, and the sound data is converted into a predetermined speech speed based on a ratio of the second frame rate to the first frame rate. The recording method according to claim 5, wherein the recording method is performed on a time axis by using a technique and recorded on the recording medium in an uncompressed sound format. The recording method according to claim 6, wherein in the sound recording control step, the identification number of the sound data of the uncompressed sound format is recorded on the recording medium with priority over the identification number of the sound data of the compressed sound format.

Images