audio filter: support additional codecs

[erankor]

support additional input codecs in audio filters, output is currently hardcoded to AAC

[aminvakil]

I'll give this a try and report back, we are currently in need of ac3 support as well.

ngx_http_vod_identify_format: failed to identify the file format /path/to/audio.ac3 while reading media header

[aminvakil]

Not sure if I should then anything else other than applying this patch, but error is the same:

ngx_http_vod_identify_format: failed to identify the file format /path/to/audio.ac3 while reading media header

[aminvakil]

file /path/to/audio.ac3 
/path/to/audio.ac3: ATSC A/52 aka AC-3 aka Dolby Digital stream, 48 kHz,, complete main (CM) 2 front/0 rear, Dolby Surround not indicated, 256 kbit/s

[aminvakil]

$ ffprobe /path/to/audio.ac3 
ffprobe version 4.3.8-0+deb11u3 Copyright (c) 2007-2024 the FFmpeg developers
  built with gcc 10 (Debian 10.2.1-6)
  configuration: --prefix=/usr --extra-version=0+deb11u3 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-pocketsphinx --enable-libmfx --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
[ac3 @ 0x55582cd31840] Estimating duration from bitrate, this may be inaccurate
Input #0, ac3, from '/path/to/audio.ac3':
  Duration: 01:30:38.05, start: 0.000000, bitrate: 256 kb/s
    Stream #0:0: Audio: ac3, 48000 Hz, stereo, fltp, 256 kb/s

Please tell me if there is anything I can do to debug further, or if you suspect file is broke.

[wnpllrzodiac]

Any update about this feature? Maybe we need to take over the job, and continue work on this feature.