[FFmpeg-trac] #9594(avcodec:new): alac encoder does no support 20bits depth

FFmpeg trac at avcodec.org
Tue Jan 11 05:38:37 EET 2022


#9594: alac encoder does no support 20bits depth
---------------------------------+---------------------------------------
             Reporter:  Michael  |                     Type:  defect
               Status:  new      |                 Priority:  normal
            Component:  avcodec  |                  Version:  unspecified
             Keywords:           |               Blocked By:
             Blocking:           |  Reproduced by developer:  0
Analyzed by developer:  0        |
---------------------------------+---------------------------------------
 Summary of the bug:
 alac decoder support 20 bits bit depth, but encoder does not.
 seems fixed bit depth in code of encoder.
 libavcodec\alacenc.c
 ---
     if (avctx->sample_fmt == AV_SAMPLE_FMT_S32P) {
         if (avctx->bits_per_raw_sample != 24)
             av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-
 sample\n");
         avctx->bits_per_raw_sample = 24;
     } else {
         avctx->bits_per_raw_sample = 16;
         s->extra_bits              = 0;
     }
 ---
 How to reproduce:
 {{{
 C:\Data\ffmpeg.exe  -i 009.caf -codec alac 009.m4a
 ffmpeg version n4.4.1-14-g5a7763bdfa-20220108 Copyright (c) 2000-2021 the
 FFmpeg developers
   built with gcc 11.2.0 (crosstool-NG 1.24.0.498_5075e1f)
   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-nonfree --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-avisynth --enable-libdav1d --enable-libdavs2 --enable-libfdk-aac
 --enable-ffnvcodec --enable-cuda-llvm --disable-frei0r --enable-libgme
 --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus
 --enable-librist --enable-libtheora --enable-libvpx --enable-libwebp
 --enable-lv2 --enable-libmfx --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 --disable-vulkan --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=20220108
   libavutil      56. 70.100 / 56. 70.100
   libavcodec     58.134.100 / 58.134.100
   libavformat    58. 76.100 / 58. 76.100
   libavdevice    58. 13.100 / 58. 13.100
   libavfilter     7.110.100 /  7.110.100
   libswscale      5.  9.100 /  5.  9.100
   libswresample   3.  9.100 /  3.  9.100
   libpostproc    55.  9.100 / 55.  9.100
 Input #0, caf, from '009.caf':
   Duration: 00:01:35.02, start: 0.000000, bitrate: 793 kb/s
   Stream #0:0: Audio: alac (alac / 0x63616C61), 44100 Hz, stereo, s32p (20
 bit), 705 kb/s
 Stream mapping:
   Stream #0:0 -> #0:0 (alac (native) -> alac (native))
 Press [q] to stop, [?] for help
 [alac @ 000002e1e6d4f000] encoding as 24 bits-per-sample
 Output #0, ipod, to '009.m4a':
   Metadata:
     encoder         : Lavf58.76.100
   Stream #0:0: Audio: alac (alac / 0x63616C61), 44100 Hz, stereo, s32p (24
 bit), 128 kb/s
     Metadata:
       encoder         : Lavc58.134.100 alac
 size=   13663kB time=00:01:34.92 bitrate=1179.2kbits/s speed= 162x
 video:0kB audio:13658kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.035743%
 }}}
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9594>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker


More information about the FFmpeg-trac mailing list