[FFmpeg-user] 回复： questions about audio filter "atempo"

[Pavel Koshevoy]

On 7/18/2012 12:11 AM, 韩瑞松 wrote:
> Thank you ,Pavel :
>        I tried the video filter "setpts" like this:
> ffmpeg -y -i youku.mp4 -analyzeduration 2G -vcodec libx264 -b 512k -r 25 -s 576x312 -aspect 576:312 -psnr -acodec libfaac -ab 64k -ar 44100 -ac 2 -vf setpts=0.5*PTS -af atempo=2 -f flv -map_chapters -1 -g 50 youku.mp4.flv
>
>
> It's output:
>
>
> ffmpeg version git-2012-07-18-56ae592 Copyright (c) 2000-2012 the FFmpeg developers
>    built on Jul 18 2012 11:12:33 with gcc 4.4.3
>    configuration: --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-libx264 --enable-libmp3lame --enable-libfaac --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvorbis --enable-libtheora --enable-shared --enable-ffplay --enable-libxvid --enable-libvpx
>    libavutil      51. 65.100 / 51. 65.100
>    libavcodec     54. 41.100 / 54. 41.100
>    libavformat    54. 17.100 / 54. 17.100
>    libavdevice    54.  1.100 / 54.  1.100
>    libavfilter     3.  2.100 /  3.  2.100
>    libswscale      2.  1.100 /  2.  1.100
>    libswresample   0. 15.100 /  0. 15.100
>    libpostproc    52.  0.100 / 52.  0.100
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'youku.mp4':
>    Metadata:
>      major_brand     : isom
>      minor_version   : 1
>      compatible_brands: isomavc1
>      creation_time   : 1941-02-22 02:53:21
>    Duration: 00:06:01.48, start: 0.000000, bitrate: 592 kb/s
>      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 576x312 [SAR 577:576 DAR 577:312], 557 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc
>      Metadata:
>        creation_time   : 1941-02-22 02:53:21
>        handler_name    : GPAC ISO Video Handler
>      Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, s16, 32 kb/s
>      Metadata:
>        creation_time   : 1941-02-22 02:53:27
>        handler_name    : GPAC ISO Audio Handler
> Please use -b:a or -b:v, -b is ambiguous
> [libx264 @ 0x9867a00] --psnr used with psy on: results will be invalid!
> [libx264 @ 0x9867a00] --tune psnr should be used if attempting to benchmark psnr!
> [libx264 @ 0x9867a00] using SAR=1/1
> [libx264 @ 0x9867a00] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle Cache64
> [libx264 @ 0x9867a00] profile High, level 2.1
> [libx264 @ 0x9867a00] 264 - core 125 r2 5f615f7 - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=3 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=50 keyint_min=5 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=abr mbtree=1 bitrate=512 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
> Output #0, flv, to 'youku.mp4.flv':
>    Metadata:
>      major_brand     : isom
>      minor_version   : 1
>      compatible_brands: isomavc1
>      encoder         : Lavf54.17.100
>      Stream #0:0(und): Video: h264 ([7][0][0][0] / 0x0007), yuv420p, 576x312 [SAR 1:1 DAR 24:13], q=-1--1, 512 kb/s, 1k tbn, 25 tbc
>      Metadata:
>        creation_time   : 1941-02-22 02:53:21
>        handler_name    : GPAC ISO Video Handler
>      Stream #0:1(und): Audio: aac ([10][0][0][0] / 0x000A), 44100 Hz, stereo, s16, 64 kb/s
>      Metadata:
>        creation_time   : 1941-02-22 02:53:27
>        handler_name    : GPAC ISO Audio Handler
> Stream mapping:
>    Stream #0:0 -> #0:0 (h264 -> libx264)
>    Stream #0:1 -> #0:1 (aac -> libfaac)
> Press [q] to stop, [?] for help
> Segmentation fault
>
>
>
>
> the same result as use -af atempo=2 only!
>
>
> How did you compile x264,ffmpeg on you server machine?
> Maybe I compiled wrong!

I don't compile x264 myself, I use whatever version is the latest from 
openSUSE additional package repositories.  I configured ffmpeg as 
follows for debugging:

cd ffmpeg-git-build;

../ffmpeg-git-src/configure --prefix=/Developer/ffmpeg --enable-gpl --enable-runtime-cpudetect --disable-optimizations --disable-stripping --enable-debug=3 --enable-libxvid --enable-libx264 --enable-libvpx --enable-libvorbis --enable-libtheora --enable-bzlib --enable-gnutls --enable-libass --enable-libcelt --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libcdio --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libdc1394 --enable-version3


This is a debug configuration, so it won't be the fastest.

You can produce a stack trace with gdb

gdb /Developer/ffmpeg

run -y -i youku.mp4 -analyzeduration 2G -vcodec libx264 -b 512k -r 25 -s 576x312 -aspect 576:312 -psnr -acodec libfaac -ab 64k -ar 44100 -ac 2 -vf setpts=0.5*PTS -af atempo=2 -f flv -map_chapters -1 -g 50 youku.mp4.flv

When it crashes type in

where


in gdb and post the results here.

     Pavel.