MPEG4

MPEG4 part2

• DivX
• Xvid
• 3ivx

MPEG4 part 10

• AVC - H.264

MPEG4 all parts

Type of frames

I-frame (intra frame)

• Full information about the image

P-frame (inter frame)

• Predictive frame
• size 50% of I frame

B-frames (inter frame)

• Bi predictive frame
• Prediction based on previous or later
• size 25% of i-frame

Gap of picture (GoP)

Closed vs Open GoP

Predictions and macroblocks

Amout of information

Macroblocks

Macroblocks

Finding a referece macroblock

Block-matching algorithm

Predictions
multiple references

Predictions information

Motion vectors example

Motion estimation

Prediction error

Direkt/skip macroblock

• SPATIAL - copy neighborhood block vector
• TEMPORAL - skipping middle frame

Transform and quantization

Prediction error

Visualization

more in google ;)

CABAC / CAVLC entropy coding

entropy coding?

Lossless compression

 type of data compressed (CAVLC)

CABAC 

• 10% more efficient
• High and main profile
• H264 / H265

CAVLC

• Base profile
• less demanding

Profiles / levels

Most important profiles

• Baseline
• Main
• High

Base

• CAVLC
• Frames: I,P

Main

• CABAC
• Frames: I,B,P
• interlaced coding

High

• quantization scaling
• 8x8, 4x4 transform adaptivity

All profiles ;)

Comparison

Levels

limitation to macroblocks/s

(bitrates)

Levels

wiki table

Example support - Apple TN 2224

Avaliable encoders

Software

• x264
• MainConcept 
• Divix H.264

Hardware

• nvenc
• VCE 2.0
• MainConcept (CUDA)
• MainConcept (OpenCL)
• Intel QuickSync

Comparison

raport