Audio channel count detection trouble

[laurfb]

Summary of the bug:
How to reproduce:
Commits 81503ac58a763a36b1f57264013b1e76acb62b68 (avcodec/utils: Require a non zero channels unless AV_CODEC_CAP_CHANNE…) broke proper audio channel count detection.

Command used & uncut console output:

D:\ffmpeg -i 00048.mts d:\output.mp4"
ffmpeg version N-100123-g7dc22fe450-g052b4c3481+2 Copyright (c) 2000-2020 the FFmpeg developers

built with gcc 10.2.0 (Rev5, Built by MSYS2 project)
configuration: --cc='ccache gcc' --cxx='ccache g++' --disable-autodetect --enable-amf --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-sdl2 --disable-debug --enable-ffnvcodec --enable-nvdec --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libx264 --enable-libx265 --enable-fontconfig --enable-libfreetype --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtwolame --enable-libvidstab --enable-libwebp --enable-gpl --enable-libxvid --enable-libopenmpt --enable-version3 --enable-decklink --enable-libfdk-aac --enable-libfribidi --enable-opencl --enable-libsrt --enable-openssl --extra-cflags=-DLIBTWOLAME_STATIC --enable-nonfree
libavutil 56. 61.100 / 56. 61.100
libavcodec 58.114.100 / 58.114.100
libavformat 58. 64.100 / 58. 64.100
libavdevice 58. 11.103 / 58. 11.103
libavfilter 7. 91.100 / 7. 91.100
libswscale 5. 8.100 / 5. 8.100
libswresample 3. 8.100 / 3. 8.100
libpostproc 55. 8.100 / 55. 8.100

[NULL @ 000001c63e715100] Decoder requires channel count but channels not set
[mpegts @ 000001c63cf48180] Failed to open codec in avformat_find_stream_info
[NULL @ 000001c63e715100] Decoder requires channel count but channels not set
[mpegts @ 000001c63cf48180] Could not find codec parameters for stream 1 (Audio: pcm_bluray (HDMV / 0x564D4448), 0 channels): unspecified sample rate
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, mpegts, from 'd:\00048.mts':

Duration: 00:00:04.71, start: 1.040000, bitrate: 22564 kb/s
Program 1

Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p(top first), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps, 50 tbr, 90k tbn, 50 tbc
Stream #0:1[0x1100]: Audio: pcm_bluray (HDMV / 0x564D4448), 0 channels
Stream #0:2[0x1200]: Subtitle: hdmv_pgs_subtitle ([144][0][0][0] / 0x0090), 1920x1080

[pcm_bluray @ 000001c63eeee940] Decoder requires channel count but channels not set
Stream mapping:

Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Stream #0:1 -> #0:1 (pcm_bluray (native) -> aac (native))

Error while opening decoder for input stream #0:1 : Invalid argument

Input file used: ​https://www9.zippyshare.com/v/HmINCifw/file.html
Input file is an Mpeg-4 AVC with 2 audio BD LPCM recorded by an XDCAM Sony camcorder.

ffmpeg build before this commit detect 2 audio channel and convert similar files without any error.

[laurfb]

Fixed in 494f868e93d1d671497d0d0884368f015eb7d31e