I had been using FFmpeg build 12665 for a long time, mostly for transcoding HD TV captures to DVD format, and recently tried new builds, but found that the encoding frames per second is a whole lot slower with the new builds - like 41 FPS with 12665, but a measly 17 FPS with newer builds. The new builds I tried are 18639, 20472, and 20584 (from three different people). All of the new builds are just too slow using similar encoding options.
What's up with that?
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I have the same problem using 10464 vs. 20584 when encoding to mpeg2 (didn't try other codecs yet).
Do you use trellis quantization?
When I take that off, speed is for both approx the same. I have the impression that 10464 simply doesn't use trellis with mpeg2 because I see no difference with or without.
FFmpeg doesn't always check if commands are supported by the given codec and ignores them without any warning.
EDIT: I mean the -trellis 1 (rate-distortion optimal quantization) command.
Yes, I use -trellis 1 with new builds and -flags +trell with old builds. Thanks for pointing that out!
Had to refresh my memory a bit.
It actually concerns a command syntax change. Weird thing is that 10464 accepts "-trellis 1" (new command) but ignores it. When I run 10464 with "-flags +trell" (old command) it's just as slow as 20584.
From revision 15263 up the old command was taken off.
Strange, for me, r12665 with -flags +trell is much faster than r20584 with -trellis 1. I'll test on different hardware.