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 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
