JP2835293B2 - Image transmission device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmission apparatus such as a transmission apparatus and a reception apparatus which compresses and encodes image data or image / audio data by a codec device and temporarily stores it in a storage device. H. The present invention relates to an image transmission apparatus that performs image processing conforming to H.261.

[0002]

2. Description of the Related Art Taking an example of an image transmitting apparatus serving as a recorder as one of image transmitting apparatuses, this type of image transmitting apparatus compresses and encodes video and audio such as news gathered on site and transmits the image. It is used in such a way that several scenes are stored in the internal storage of the device and then transmitted to a remote location at a low transmission rate. However, when a photograph taken at a compression rate of 1.5 Mbps is transmitted at a low transmission rate of 64 Kbps using an ISDN digital network, a transmission time that is about 24 times as long as the photographing time is required. Since transmission takes a long time and the line usage fee is expensive,
It is desirable that not only the entire photographed scene be transmitted, but also that only important scenes be selected and that the scenes be subjected to rough editing such as changing the order of the scenes before transmission.

The video and audio captured by the image transmitting apparatus are processed by a built-in CPU for each unit processing bit number such as 8 bits or 16 bits.
However, H. The compressed image data conforming to the H.261 standard is a variable-length coding algorithm in bit units. Therefore, if the scene to be transmitted is simply extracted by the CPU processing, the total number of bits of the bit stream of the image compressed data of one scene is determined by the CPU. Is not a multiple of the unit processing bit number, and a fraction often occurs at the end of the bit stream. If you connect to the next scene while leaving the fractional bits or simply removing the fractional bits, the bit stream after that part cannot be read correctly when played back, It will be disrupted and collapsed. Therefore, conventionally, H. 2
When reproducing or transmitting image data that has been compression-encoded according to the 61 standard, the operation of reproducing and stopping for each scene is performed by hardware or software by repeating it.

[0004]

However, in this case, since the reproduction is performed after resetting for each scene, the images and sounds become discontinuous at the time when the scene is switched, and the image stops or the sound is stopped. There was a problem that noise occurred.

[0005]

According to the present invention, the total number of bits of a bit stream of each scene stored in a storage device is represented by C
Automatic adjustment is performed so as to be a multiple of the number of unit processing bits of the PU, or a multiple of the number of bits of the interval of the identifier of the data content, so that seams between scenes do not become discontinuous. That is, according to the present invention, an H.264 bit stream including a PSC code inserted at the head of a frame is used. Image data compressed and coded according to the H.261 standard
In the image transmission device which temporarily stores the image data in the internal storage device by the U control, the bit after the last PSC code of the bit stream of the image data of one scene is deleted, and the total number of the bit stream is changed to the unit processing bit of the CPU. Until a multiple of the number, bits of zero data are added to the end of the bit stream, and the image data is stored in a storage device. Also, the present invention provides a method in which compression-encoded audio data and a PSC
The code is inserted and Image transmission apparatus for temporarily storing image / audio data composed of a bit stream in which image data compressed and encoded according to the H.261 standard and data content identifiers are inserted at predetermined intervals in an internal storage device under CPU control And the number of bits in the identifier interval is C
In the image transmission apparatus which is a multiple of the unit processing bit number of the PU, the bits after the last PSC code of the bit stream of the video and audio data of one scene are deleted, and the total number of the bit stream is determined by the number of bits of the interval of the identifier. Until it becomes a multiple of, a bit of zero data is added to the end of the bit stream, and then the video and audio data is stored in the storage device.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below, taking an image transmitting apparatus having a recording function as an example of an image transmitting apparatus. FIG. 1 is a conceptual diagram illustrating an example of a bit stream 10 of image data of one scene that has been compression-encoded,
The last part of the bit stream 10 immediately after being cut by the hardware is shown. In the bit stream 10, a PSC code 12 representing the head position of a frame is inserted at the beginning of each frame. The end of the bit stream 10 of one scene is cut off when the recording operation of the image data supplied from the video camera is stopped.

In the image transmission apparatus according to the present invention, when such image data is input from a video camera or the like, the CPU of the image transmission apparatus determines whether the end of the bit stream for each scene is determined by the hardware operation. After performing the following processing, the bit stream is sequentially stored in the storage device. (1) Search for the last PSC code 12e,
The bits after the code 12e are deleted. (2) Bits of zero data are added to the end of the bit stream 10 until the total number of the bit stream 10 becomes a multiple of the unit processing bit number of the CPU. That is, as shown in FIG. 2, a bit string 14 of zero data is added after the bit where the last PSC code 12e exists. (3) The bit stream 10 of the image data is stored in the storage device. These processes may be performed before the image data is stored in the storage device when the image data is input from the video camera to the transmission device. It is also possible to read and rewrite only the bit stream.

In this manner, the bit stream of each scene is stored in the storage device after its end is processed so as to be a multiple of the unit processing bit number of the CPU. As a result, since there is no fraction with respect to the unit processing bit number of the CPU, the data reading operation is performed correctly. P
The bit string 14 of zero data preceding the SC code does not adversely affect image display. Therefore, when some necessary scenes are selected from the scenes stored in the storage device, and these scenes are connected in an arbitrary order to be reproduced or transmitted as one continuous image / audio data, the scenes are selected. The seams between them are not discontinuous. In this example, as shown in FIG. 3, immediately after the bit string 14 of the zero data of the bit stream 10 of the first scene,
The bit stream 20 of the second scene will be concatenated.

On the other hand, FIG. 4 shows an example of a bit stream 30 of video / audio data obtained by mixing video data and audio data which are both compression-coded. The bit stream 30 of the video and audio data of one scene that has been compression-encoded includes:
A PSC code 32 indicating the head position of the frame is inserted, and identifiers H indicating types of data contents such as images, sounds, and controls are inserted at predetermined intervals D. The number of bits in the interval D is, for example, the unit processing bit number of the CPU is 8
In the case of bits, it is selected to be a multiple of the unit processing bit number of the CPU, such as 512 bits (64 bytes). In the case of the bit stream 30 including such image and audio data, the CPU processes the bit number of the bit stream 30 of each scene so as to be a multiple of the bit number of the interval D of the identifier H.

Assume that the unit number of processing bits of the CPU is 8 bits and the number of bits of the interval D is 512 bits. As shown in FIG. 4, when the end of the bit stream 30 is cut off by hardware, the CPU searches for the last PSC code 32e and deletes bits subsequent to the PSC code 32e. Then, as shown in FIG. 5, a bit string 34 of zero data is added to the end so that the total number of bit streams 30 is a multiple of the number of bits of the interval D, and then the bit stream 30 is stored in the storage device. As a result, even when bit streams of a plurality of scenes are concatenated, a fraction with respect to the unit processing bit number of the CPU does not appear, and the interval D of the identifier H does not shift. After the first scene bitstream 30 the second
When the bit stream 40 of the scene of FIG.
As shown in the figure, the data is connected after the bit string 34 of zero data. Therefore, when several scenes among the scenes stored in the storage device are connected in an arbitrary order and are reproduced and transmitted as a continuous video and audio data, a discontinuity between the scenes does not occur.

Although the description has been given of the example of the transmitting apparatus, the present invention is not limited to the transmitting apparatus but can be applied to the receiving apparatus.
That is, H. For received image data that has been compression-encoded in accordance with the H.261 standard and whose tail has not been processed, the total number of bit streams in one scene is reduced to a multiple of the unit processing bit number of the CPU, or the interval D of the identifier H is Until the number of bits becomes a multiple, the bit of zero data may be added to the end, and the image data may be stored in a storage device inside the receiving device. In this way, when several scenes are selected and rearranged, or a part of each scene is extracted and edited, and played back as a continuous image data, the seam between the scenes is discontinuous. Can be prevented.

[0012]

According to the present invention, when stored in the internal storage device, the total number of bits of the bit stream of each scene is a multiple of the unit processing bit number of the CPU or the number of bits of the interval D of the identifier H. Automatically adjusted to be a multiple of. For this reason, even if some necessary scenes are rearranged in an arbitrary order, edited into a series of video and audio data, reproduced, and transmitted, the seams between the scenes do not become discontinuous. Then, the images are smoothly connected without stopping at a portion between the scenes, and no noise is generated in the sound. The transmission device to which the present invention is applied can save the trouble of re-editing on the receiving side, so that it is particularly useful for the transmission of time-sensitive news material.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a bit stream of image data immediately after shredding.

FIG. 2 is a diagram showing the end of the same bit stream after inserting zero data.

FIG. 3 is a diagram showing a state where a bit stream of another scene is connected to the same end.

FIG. 4 is a diagram showing a bit stream of another image / sound data immediately after cutting;

FIG. 5 is a diagram showing the end of the same bit stream after inserting zero data.

FIG. 6 is a diagram showing a state where a bit stream of another scene is connected to the same end.

[Explanation of symbols]

 H identifier D interval of identifier 30 bit stream of first scene 32 PSC code 32e last PSC code 34 bit string of inserted zero data

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04N ^7/ 24-7/68 H04N ^5/ 91-5/95 H04N 7/14 H03M 7/30

Claims (2)

(57) [Claims] 1. An H.264 frame comprising a bit stream having a PSC code inserted at the beginning of a frame. In an image transmission apparatus in which image data compressed and encoded according to the H.261 standard is temporarily stored in an internal storage device under CPU control, bits after the last PSC code in a bit stream of image data of one scene are deleted. And adding the bit of zero data to the end of the bit stream until the total number of the bit stream becomes a multiple of the unit processing bit number of the CPU, and then storing the image data in the storage device. Image transmission device. 2. The compression-encoded audio data and a PSC code inserted at the beginning of a frame, Image transmission apparatus for temporarily storing image / audio data composed of a bit stream in which image data compressed and encoded according to the H.261 standard and data content identifiers are inserted at predetermined intervals in an internal storage device under CPU control In the image transmission apparatus in which the number of bits of the identifier interval is a multiple of the unit processing bit number of the CPU, the bits after the last PSC code of the bit stream of the video and audio data of one scene are deleted, and Until the total number of streams becomes a multiple of the number of bits of the identifier interval, bits of zero data are added to the end of the bit stream, and then the video and audio data is stored in the storage device. Image transmission device.