[FFmpeg-trac] #10276(undetermined:new): Reversed channel order with showspectrumpic mode=separate

[FFmpeg]

#10276: Reversed channel order with showspectrumpic mode=separate
-------------------------------------+-------------------------------------
             Reporter:               |                     Type:  defect
  SomeHumanPerson                    |
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:               |               Blocked By:
  showspectrumpic                    |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:

 Multi-channel spectrogram images produced by "showspectrumpic" with
 "mode=separate" display the individual channels ordered from the bottom up
 instead of from the top down.  This is the opposite of how "showwavespic"
 (and any other software I am familiar with) orders the channels.

 With a common 5.1(side) channel layout, for example, "showwavespic" in
 "split" mode displays FL-FR-C-LFE-SL-SR in order from the top down.

 But "showspectrumpic" in "separate" mode displays the channels in the
 reverse order, from the bottom up.


 How to reproduce:
 {{{
 % ffmpeg -hide_banner -i "F:\Test.wav" -lavfi
 showspectrumpic=mode=separate:fscale=log:size=1200x1536 -frames:v 1
 -update 1 Spectrogram.png
 Input #0, wav, from 'F:\Test.wav':
   Metadata:
     encoder         : Lavf59.35.100
   Duration: 01:45:37.26, bitrate: 6912 kb/s
   Stream #0:0: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 48000 Hz,
 5.1(side), s32 (24 bit), 6912 kb/s
 Stream mapping:
   Stream #0:0 (pcm_s24le) -> showspectrumpic:default
   showspectrumpic:default -> Stream #0:0 (png)
 Press [q] to stop, [?] for help

 % ffmpeg -v 9 -loglevel 99 -i "F:\Test.wav"
 ffmpeg version 2023-03-20-git-57afccc0ef-full_build-www.gyan.dev Copyright
 (c) 2000-2023 the FFmpeg developers
   built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
   configuration: --enable-gpl --enable-version3 --enable-static --disable-
 w32threads --disable-autodetect --enable-fontconfig --enable-iconv
 --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma
 --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt
 --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray
 --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libdav1d
 --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e
 --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265
 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl
 --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-
 libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-
 liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-
 amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec
 --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-
 libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-
 libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-
 libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora
 --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-
 libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex
 --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite
 --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-
 chromaprint
   libavutil      58.  4.100 / 58.  4.100
   libavcodec     60.  6.101 / 60.  6.101
   libavformat    60.  4.100 / 60.  4.100
   libavdevice    60.  2.100 / 60.  2.100
   libavfilter     9.  4.100 /  9.  4.100
   libswscale      7.  2.100 /  7.  2.100
   libswresample   4. 11.100 /  4. 11.100
   libpostproc    57.  2.100 / 57.  2.100
 Splitting the commandline.
 Reading option '-v' ... matched as option 'v' (set logging level) with
 argument '9'.
 Reading option '-loglevel' ... matched as option 'loglevel' (set logging
 level) with argument '99'.
 Reading option '-i' ... matched as input url with argument 'F:\Test.wav'.
 Finished splitting the commandline.
 Parsing a group of options: global .
 Applying option v (set logging level) with argument 9.
 Successfully parsed a group of options.
 Parsing a group of options: input url F:\Test.wav.
 Successfully parsed a group of options.
 Opening an input file: F:\Test.wav.
 [NULL @ 000002a10deb52c0] Opening 'F:\Test.wav' for reading
 [file @ 000002a10deb5900] Setting default whitelist 'file,crypto,data'
 Probing wav score:100 size:2048
 [wav @ 000002a10deb52c0] Format wav probed with size=2048 and score=100
 [wav @ 000002a10deb52c0] Before avformat_find_stream_info() pos: 138 bytes
 read:65674 seeks:1 nb_streams:1
 [wav @ 000002a10deb52c0] parser not found for codec pcm_s24le, packets or
 times may be invalid.
     Last message repeated 1 times
 [wav @ 000002a10deb52c0] All info found
 [wav @ 000002a10deb52c0] stream 0: start_time: NOPTS duration: 6337.26
 [wav @ 000002a10deb52c0] format: start_time: NOPTS duration: 6337.26
 (estimate from stream) bitrate=6912 kb/s
 [wav @ 000002a10deb52c0] After avformat_find_stream_info() pos: 204438
 bytes read:295050 seeks:1 frames:50
 Input #0, wav, from 'F:\Test.wav':
   Metadata:
     encoder         : Lavf59.35.100
   Duration: 01:45:37.26, bitrate: 6912 kb/s
   Stream #0:0, 50, 1/48000: Audio: pcm_s24le ([1][0][0][0] / 0x0001),
 48000 Hz, 5.1(side), s32 (24 bit), 6912 kb/s
 Successfully opened the file.
 At least one output file must be specified
 [AVIOContext @ 000002a10deb3400] Statistics: 295050 bytes read, 1 seeks
 }}}
 I have reproduced this with an assortment of 5.1 and 7.1 input files in
 various formats (ac3, dts, wav/w64).  Any simple channel-mapping test file
 should work fine.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10276>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker