Brief introduction of H264 codec frame

After reading the introduction of H264/AVC codec, I just left the following three articles in my mind:

1, H264 does not understand how to implement a codec, just a coded video bit stream syntax, and the Bitstream decoding method, this is similar to MPEG.

2, H264 and once the standard (such as H261, H263, MPEG-1, MPEG-4) codec implementation process is not much different, the basic difference is the details of each function block.

3, H264 is to use the complexity of implementation to obtain a significant improvement in compression performance. (As for the assessment of complexity, it will be introduced later)

The following is a description of the encoder block diagram for H264:

The encoder is still a mixed-coding method that transforms and predicts. In Figure 6.1, the input frame or field FN is handled by the encoder as a macro block. First, it is processed by the method of pre-measurement in frame or inter-frame. Assuming the use of inter-frame pre-measured encoding, its pre-measured value pred is the current slice of the previously encoded reference image by the motion compensation (MC), the reference image is expressed in F ' n-1. The pre-measured value pred and the current block after subtracting, resulting in a residual block DN, after the block transformation, quantization produces a set of quantization transformation coefficient x, and then by the entropy encoding, and the decoding of some of the required header information together to form a compressed code stream, through the NAL (Network Adaptive Layer) for transmission and storage.

H264 's decoder block diagram:

In Figure 6.2, the NAL output of the encoder H264 bits through the entropy decoding the quantization of a set of transformation coefficient x, and then by the inverse quantization, inverse transformation, to obtain residual d ' N. Using the header information decoded from this bitstream, the decoder generates a pre-measured block pred, which is the same as the original pred in the encoder. When the decoder produces the pred and residual d ' n is added, the UF ' n is obtained, then filtered, and finally the decoded output image f ' n is obtained.

* Above pictures from "H264 and MPEG-4 VIDEO COMPRESSION"

Brief introduction of H264 codec frame