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View Full Version : Please can anyone answer this question?


chacademus
15th February 2002, 23:48
Anyone know much about how encoders work? What I need to know is whether each mpeg-1 encoder has some form of algorithm it uses for encoding every video clip in terms of i-frames, b-frames and p-frames, and do they always stick to this? I have noticed that for example tmpgenc has a difference of 18 between its sucessive i-frames whereas lsx has a difference of 12. This seems to be constant but I would like to hear it from someone else who more than likely has more knowledge about this than me. Also would this have an effect on encoding speed and encoding quality? Any help would be greatly appreciated! Thankyou. :)

movmasty
16th February 2002, 06:10
you can set that number in every mpg encoder
es. 3 P frames between I,and 2 B frames in between, gives 12(4x3)
5 P frames, and 2 B, gives 18(6x3)
standard settings are 3P+2B - 4P+2b for film or pal(12-15)
4P+2b - 5p+2b for ntsc(15/18)
also mpg with only I and P frames are nice, even size is bigger.
5P+3B or 4P+4B for high compression