I have recently updated ffmpeg from version 2.0.2 to the most recent release 2.7. I installed it using the same building configuration as the old version and the same codecs version (libvpx and h264). When I tried to transcode an mp4 video to webm, I found out that the speed of the new version is significantly lower (3 times) than the old one. I run this on two identical 8 core machines (Intel(R) Xeon(R) CPU E5-2680 v2 @ 2.80GHz) - OS: Ubuntu 14.04. Below is the command I run:
/usr/local/bin/ffmpeg -i in.mp4 -f webm -vcodec libvpx -b:v 1000K out.webm
These are the outputs for the two versions:
v 2.0.2
ffmpeg version 2.0.2 Copyright (c) 2000-2013 the FFmpeg developers
built on Jan 7 2015 13:51:25 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
configuration: --disable-ffplay --disable-ffserver --enable-libxvid --enable-gpl --enable-nonfree --enable-pthreads --enable-libmp3lame --enable-libx264 --enable-libfaac --enable-zlib --enable-avfilter --enable-libfreetype --enable-libfdk_aac --enable-libtheora --enable-libvorbis --enable-libvpx --enable-pic --enable-shared
libavutil 52. 38.100 / 52. 38.100
libavcodec 55. 18.102 / 55. 18.102
libavformat 55. 12.100 / 55. 12.100
libavdevice 55. 3.100 / 55. 3.100
libavfilter 3. 79.101 / 3. 79.101
libswscale 2. 3.100 / 2. 3.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 3.100 / 52. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'in.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf55.12.100
Duration: 00:00:10.19, start: 0.000000, bitrate: 1724 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 1480 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 253 kb/s
Metadata:
handler_name : SoundHandler
[libvpx @ 0x22f3760] v1.3.0
Output #0, webm, to 'out.webm':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf55.12.100
Stream #0:0(und): Video: vp8 (libvpx), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 1000 kb/s, 1k tbn, 29.97 tbc
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: vorbis (libvorbis), 44100 Hz, stereo, fltp
Metadata:
handler_name : SoundHandler
Stream mapping:
Stream #0:0 -> #0:0 (h264 -> libvpx)
Stream #0:1 -> #0:1 (aac -> libvorbis)
Press [q] to stop, [?] for help
frame= 302 fps= 23 q=0.0 Lsize= 1445kB time=00:00:10.18 bitrate=1161.9kbits/s
video:1304kB audio:128kB subtitle:0 global headers:4kB muxing overhead 0.644833%
v 2.7
ffmpeg version 2.7 Copyright (c) 2000-2015 the FFmpeg developer built with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
configuration: --disable-ffplay --disable-ffserver --enable-libxvid --enable-gpl --enable-nonfree --enable-libmp3lame --enable-libx264 --enable-libfaac --enable-zlib --enable-libass --enable-pthreads --enable-avfilter --enable-libfreetype --enable-libfdk_aac --enable-libtheora --enable-libvorbis --enable-libvpx --enable-pic --enable-shared --enable-openssl
libavutil 54. 27.100 / 54. 27.100
libavcodec 56. 41.100 / 56. 41.100
libavformat 56. 36.100 / 56. 36.100
libavdevice 56. 4.100 / 56. 4.100
libavfilter 5. 16.101 / 5. 16.101
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 2.100 / 1. 2.100
libpostproc 53. 3.100 / 53. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'in.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf56.36.100
Duration: 00:00:10.19, start: 0.000000, bitrate: 1596 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 1480 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
Metadata:
handler_name : SoundHandler
[libvpx @ 0xfe4640] v1.3.0
Output #0, webm, to 'out.webm':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf56.36.100
Stream #0:0(und): Video: vp8 (libvpx), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 1000 kb/s, 29.97 fps, 1k tbn, 29.97 tbc (default)
Metadata:
handler_name : VideoHandler
encoder : Lavc56.41.100 libvpx
Stream #0:1(und): Audio: vorbis (libvorbis), 44100 Hz, stereo, fltp (default)
Metadata:
handler_name : SoundHandler
encoder : Lavc56.41.100 libvorbis
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> vp8 (libvpx))
Stream #0:1 -> #0:1 (aac (native) -> vorbis (libvorbis))
Press [q] to stop, [?] for help
frame= 302 fps=8.3 q=0.0 Lsize= 1410kB time=00:00:10.18 bitrate=1133.4kbits/s
video:1274kB audio:123kB subtitle:0kB other streams:0kB global headers:4kB muxing overhead: 0.909304%
I tried ffmpeg 2.6.3 and the performance the same as for 2.7. Also it looks like when I transcode webm to mp4 2.7 is 30% faster than webm.
I tried to look if there are building configuration options for the new version but couldn't find anything.
Can anyone suggest a possible reason for the worse speed performance of the new version when transcoding to webm?
I have run the command with -loglevel 99 and I checked the logs. I found out a difference in the vpx codec option:
v2.0.2 :
v2.7 :
It looks like the new version of ffmpeg sets this to 1 by default. To manually set this parameter from ffmpeg I had to add the option: "-speed ". The description of this option is in http://www.webmproject.org/docs/webm-sdk/group__vp8__encoder.html . I found the reference of the speed option in ffmpeg only in the ffmpeg developers mailing list: http://ffmpeg.org/pipermail/ffmpeg-devel/2011-January/105630.html . With the command:
I get the same performance in ffmpeg 2.0.2 and 2.7. I tried to increase the value and I achieved significant speed improvement. From a visual assessment the quality seems to be guaranteed by the b:v option (bit rate).