On 11/23/15, Ryan Williams <r...@ryanwilliams.id.au> wrote: > I am getting an unexpected number of samples in the output of the > 'acrossfade' filter. > In the following example I would expect acrossfade.wav to contain 72,000 > samples but it only contains 70,976 samples. > Am I doing something wrong? > > [root@ryan ff]# ffmpeg \ > -y \ > -vn \ > -filter_complex " \ > aevalsrc='exprs=sin(440*2*PI*t):s=8000', atrim='duration=5' [a0]; \ > aevalsrc='exprs=sin(440*2*PI*t):s=8000', atrim='duration=5' [a1]; \ > aevalsrc='exprs=sin(440*2*PI*t):s=8000', atrim='duration=5' [a2]; \ > aevalsrc='exprs=sin(440*2*PI*t):s=8000', atrim='duration=5' [a3]; \ > [a0][a1] concat='n=2:v=0:a=1' [output1]; \ > [a2][a3] acrossfade='ns=8000' [output2] \ > " \ > -map '[output1]' concat.wav \ > -map '[output2]' acrossfade.wav > > ffmpeg version 2.8.2-static http://johnvansickle.com/ffmpeg/ Copyright (c) > 2000-2015 the FFmpeg developers > built with gcc 5.2.1 (Debian 5.2.1-23) 20151028 > configuration: --enable-gpl --enable-version3 --disable-shared > --disable-debug --enable-runtime-cpudetect --enable-libmp3lame > --enable-libx264 --enable-libx265 --enable-libwebp --enable-libspeex > --enable-libvorbis --enable-libvpx --enable-libfreetype --enable-fontconfig > --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb > --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwbenc > --enable-gray --enable-libopenjpeg --enable-libopus --enable-libass > --enable-gnutls --enable-libvidstab --enable-libsoxr --enable-frei0r > --enable-libfribidi --disable-indev=sndio --disable-outdev=sndio --cc=gcc > libavutil 54. 31.100 / 54. 31.100 > libavcodec 56. 60.100 / 56. 60.100 > libavformat 56. 40.101 / 56. 40.101 > libavdevice 56. 4.100 / 56. 4.100 > libavfilter 5. 40.101 / 5. 40.101 > libswscale 3. 1.101 / 3. 1.101 > libswresample 1. 2.101 / 1. 2.101 > libpostproc 53. 3.100 / 53. 3.100 > Output #0, wav, to 'concat.wav': > Metadata: > ISFT : Lavf56.40.101 > Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 8000 Hz, mono, > s16, 128 kb/s (default) > Metadata: > encoder : Lavc56.60.100 pcm_s16le > Output #1, wav, to 'acrossfade.wav': > Metadata: > ISFT : Lavf56.40.101 > Stream #1:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 8000 Hz, mono, > s16, 128 kb/s (default) > Metadata: > encoder : Lavc56.60.100 pcm_s16le > Stream mapping: > concat -> Stream #0:0 (pcm_s16le) > acrossfade -> Stream #1:0 (pcm_s16le) > Press [q] to stop, [?] for help > size= 156kB time=00:00:10.00 bitrate= 128.1kbits/s > video:0kB audio:295kB subtitle:0kB other streams:0kB global headers:0kB > muxing overhead: unknown > > [root@ryan ff]# sox --info -s concat.wav > 80000 > > [root@ryan ff]# sox --info -s acrossfade.wav > 70976
You can get same info and more with astats filter. Issue should be fixed, thanks for reporting. > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
