performance improvement encoding MPEG4 or RV40?

[hellfred]

Hi there
I know that mplayer/libavcodec is much faster in decoding when running on linux. What are your findings when it comes to encoding?
I am encoding some TV-captures (Philips chip :( ) to MPEG4 using XviD or Helix Producer 10 on win32, using a P4 3GHz HT mashine. Will i encounter significant speedups when unsing linux? Is it worth compiling the helix producer SDK? Will xvid/libavcodec be faster than on win32 via vfw interface? Will i still encounter them when i use knoppix with a permanent home to compile the encoders in there and start with compressed image copied to NTFS partition (so the filesystem still has to be decompressed, but the slow I/O form CDRom is avoided.)?

Hellfred

[doug_s]

My own experience with comparing xvid encoding speeds between windows and linux is that there is very little difference. Windows was sometimes a few fps faster but that was all.

[hellfred]

Hi doug_s
Did you use gcc or intel compiler to compile xvid under linux? May the performance difference arise from the compiler? After seeing the different performance in decoding, i had thought that maybe the vfw or dshow windows APIs might be some sort of bottleneck on win32 that can be avoided under linux, resulting in a performance improvement. Did you try libavcode via ffmpeg or mencoder, too?

Hellfred

[doug_s]

I've used both intel and gcc to compile xvid under linux. The developers stated in a thread in the xvid forum that because they use assembly language routines to optimize their code changing compilers only makes about a two percent speed difference. My results bore that out. You can search the xvid forum to see koepis' comments.

I used to use ffmpeg for all my linux encoding until recently. Now I try both (xvid and ffmeg) and pick the one with the best video quality. Most of the time there isn't much difference but sometimes you see a video that looks better with one than the other. As far as speed goes, ffmpeg is a little faster with default options but if you use some of the high quality options like trellis it slows down alot.

I've never tried ffmpeg in windows because using a command line encoder in windows seems a little silly when you have a tool like gordian knot available. There are some people here who use mencoder in windows tho, maybe they could tell you if they see a speed difference.

There are performance differences in linux depending on which tool you use. Alot of people see mencoder run faster than transcode even using the same codec and similar options. I use transcode sometimes anyway because the inverse telecine works better than with mencoder on some video.

[hellfred]

I forgot about the critical parts coded in asm discussion in the xvid thread when asking for the compiler. You are right. Now i have compiled mencoder on my system with support for libavcodec, xvid and lame. So I am ready to start experinmenting myself. I will start a new thread with encoding settings for mencoder. Would be nice if you could give me a hand for some encoding settings there.

Hellfred