[FFmpeg-trac] #4940(ffmpeg:new): Slower preset runs longer, but makes larger file
FFmpeg
trac at avcodec.org
Sat Oct 17 00:13:06 CEST 2015
#4940: Slower preset runs longer, but makes larger file
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Reporter: Larek | Type: defect
Status: new | Priority: normal
Component: ffmpeg | Version: unspecified
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Summary of the bug:x264 preset failure
How to reproduce:
{{{
% ffmpeg -i input -preset slow -crf 18 -c:v libx264 output-S
% ffmpeg -i input -preset slower -crf 18 -c:v libx264 output-Sr
% ffmpeg -i input -preset veryslow -crf 18 -c:v libx264 output-Vs
% ffmpeg -i input -preset placebo -crf 18 -c:v libx264 output
ffmpeg version N-75976-gd59bfcd
Zeranoe Static Win32 build (linked from this site)
built on 13-10-2015
ffmpeg-20151013-git-d59bfcd-win32-static.7z
}}}
Slow took 6min produced 261MB file
Slower took 13min produced 252MB file
Veryslow took 24min produced 230MB file
Placebo took 83min produced 237MB file
https://trac.ffmpeg.org/wiki/Encode/H.264 , says that
{{{
A slower preset will provide better compression
}}}
As time ''for me'' isn't a factor compared to quality and file size, I'll
take that ~1% better {{{Placebo}}} should do over {{{Veryslow}}}. Heck if
ffmpeg had a {{{Ludicrous}}} preset that took a similar job 24-48hours for
a 4% gain I'd be using it.
But just to see how much better {{{Placebo}}} has been doing, I ran a
duplicate {{{Veryslow}}} job. {{{Placebo}}} is producing a '''larger'''
output from the same input file and settings than {{{Veryslow}}} job!
More Detail
Input #0, matroska,webm, from 'Disk02_(ep05-09)-001.mkv':
Metadata:
encoder : libebml v1.2.2 + libmatroska v1.3.0
creation_time : 2015-10-15 14:15:42
Duration: 00:23:11.04, start: 0.000000, bitrate: 7332 kb/s
Stream #0:0: Video: mpeg2video (Main), yuv420p(tv), 720x576 [SAR 16:15
DAR 4:3], max. 9000 kb/s, 50 fps, 50 tbr, 1k tbn, 50 tbc (default)
Stream #0:1: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s (default)
Stream mapping:
Stream #0:0 -> #0:0 (mpeg2video (native) -> h264 (libx264))
Stream #0:1 -> #0:1 (ac3 (native) -> vorbis (libvorbis))
--
Ticket URL: <https://trac.ffmpeg.org/ticket/4940>
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