Encoded Output Delivered as a Bit Stream - A Practical Guide to Video and Audio Compression - page 262

Figure 14-12 H.264 bit-stream output. Source: courtesy of Tektronix.

14.9 Summary of How Encoders Work

So to review where we have arrived now that we are at the end of this chapter, let's take
a sequence of video and describe the step-by-step process of compression.

1. Divide the video sequence into groups of pictures.
2. Process the I-frame at the start of the GOP.
3. Locate the next P-frame in the GOP and code that.
4. Code the intervening B-frames.
5. Step forward to the next P-frame and continue until the end of the GOP.

For each frame,

1. Divide the frame into macroblocks.
2. Locate similar macroblocks nearby to reduce redundancy.
3. Separate the luma and chroma for each block.
4. Apply a transformation to each macroblock.
5. Quantize and entropy code the macroblocks.
6. Store the coded bit stream in an elementary stream.