[FFmpeg-trac] #10153(undetermined:closed): AAC-LATM: Mono identified as stereo

[FFmpeg]

#10153: AAC-LATM: Mono identified as stereo
-------------------------------------+-------------------------------------
             Reporter:  Peter        |                    Owner:  (none)
  Krefting                           |
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  git-master   |               Resolution:  invalid
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Changes (by Balling):

 * status:  new => closed
 * resolution:   => invalid

Comment:

 Mono HE-AAC is always treated as stereo! Because it can become stereo at
 any point in the future. All, aac fixed, aac float and FDK treat mono as
 stereo, ALWAYS.

 And it does print

 PS C:\Users\XXXX> ffplay.exe -v verbose mono.aac
 ffplay version N-109662-g2c3107c3e9-20230125 Copyright (c) 2003-2023 the
 FFmpeg developers
   built with gcc 12.2.0 (crosstool-NG 1.25.0.90_cf9beb1)
   configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static
 --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64
 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug
 --enable-shared --disable-static --disable-w32threads --enable-pthreads
 --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype
 --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig
 --enable-libvorbis --enable-opencl --disable-libpulse --enable-libvmaf
 --disable-libxcb --disable-xlib --enable-amf --enable-libaom --enable-
 libaribb24 --enable-avisynth --enable-chromaprint --enable-libdav1d
 --enable-libdavs2 --disable-libfdk-aac --enable-ffnvcodec --enable-cuda-
 llvm --enable-frei0r --enable-libgme --enable-libkvazaar --enable-libass
 --enable-libbluray --enable-libjxl --enable-libmp3lame --enable-libopus
 --enable-librist --enable-libssh --enable-libtheora --enable-libvpx
 --enable-libwebp --enable-lv2 --disable-libmfx --enable-libvpl --enable-
 openal --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-
 libopenh264 --enable-libopenjpeg --enable-libopenmpt --enable-librav1e
 --enable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr
 --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d
 --disable-libdrm --disable-vaapi --enable-libvidstab --enable-vulkan
 --enable-libshaderc --enable-libplacebo --enable-libx264 --enable-libx265
 --enable-libxavs2 --enable-libxvid --enable-libzimg --enable-libzvbi
 --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-
 ldflags=-pthread --extra-ldexeflags= --extra-libs=-lgomp --extra-
 version=20230125
   libavutil      57. 44.100 / 57. 44.100
   libavcodec     59. 57.100 / 59. 57.100
   libavformat    59. 36.100 / 59. 36.100
   libavdevice    59.  8.101 / 59.  8.101
   libavfilter     8. 54.100 /  8. 54.100
   libswscale      6.  8.112 /  6.  8.112
   libswresample   4.  9.100 /  4.  9.100
   libpostproc    56.  7.100 / 56.  7.100
 Initialized direct3d renderer.
 '''[aac_latm @ 000001ade9754e40] Treating HE-AAC mono as stereo.=0/0
 '''Input #0, loas, from 'mono.aac':
   Duration: N/A, bitrate: N/A
   Stream #0:0: Audio: aac_latm (HE-AACv2), 48000 Hz, stereo, fltp
 [ffplay_abuffer @ 000001ade9774200] tb:1/48000 samplefmt:fltp
 samplerate:48000 chlayout:mono
 [ffplay_abuffersink @ 000001ade975bf80] auto-inserting filter
 'auto_aresample_0' between the filter 'ffplay_abuffer' and the filter
 'ffplay_abuffersink'
 [auto_aresample_0 @ 000001ade9775bc0] ch:1 chl:mono fmt:fltp r:48000Hz ->
 ch:1 chl:mono fmt:s16 r:48000Hz
 [aac_latm @ 000001ade9757c40] Treating HE-AAC mono as stereo.
 [ffplay_abuffer @ 000001ade975bf80] tb:1/48000 samplefmt:fltp
 samplerate:48000 chlayout:stereo
 [ffplay_abuffersink @ 000001adf2586580] auto-inserting filter
 'auto_aresample_0' between the filter 'ffplay_abuffer' and the filter
 'ffplay_abuffersink'
 [auto_aresample_0 @ 000001ade9776280] ch:2 chl:stereo fmt:fltp r:48000Hz
 -> ch:2 chl:stereo fmt:s16 r:48000Hz
 Created 640x480 texture with SDL_PIXELFORMAT_ARGB8888.
 [AVIOContext @ 000001ade975c1c0] Statistics: 32768 bytes read, 0 seeks
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10153#comment:1>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker