#11559: Vorbis Comment fields renamed
---------------------------------------+----------------------------------
Reporter: Timon Martins | Type: defect
Status: new | Priority: normal
Component: avformat | Version: 7.1
Keywords: ogg opus flac | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
---------------------------------------+----------------------------------
Summary of the bug:
When writing metadata to an opus file and afterwards reading that same
metadata, the field names do not match.
Note how it says `description` in the output of the second command, but
`comment` in the output of the third.
How to reproduce:
{{{
$ ffprobe -show_entries stream_tags little-metadata.opus 2> /dev/null
[STREAM]
TAG:language=eng
TAG:encoder=Lavf61.7.100
[/STREAM]
$ ffmpeg -i little-metadata.opus -map 0 -c copy -metadata "description=A
good description" more-metadata.opus
ffmpeg version 7.1.1 Copyright (c) 2000-2025 the FFmpeg developers
built with Apple clang version 15.0.0 (clang-1500.1.0.2.5)
configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/7.1.1_2 --enable-
shared --enable-pthreads --enable-version3 --cc=clang --host-cflags=
--host-ldflags='-Wl,-ld_classic' --enable-ffplay --enable-gnutls --enable-
gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-
libdav1d --enable-libharfbuzz --enable-libjxl --enable-libmp3lame
--enable-libopus --enable-librav1e --enable-librist --enable-librubberband
--enable-libsnappy --enable-libsrt --enable-libssh --enable-libsvtav1
--enable-libtesseract --enable-libtheora --enable-libvidstab --enable-
libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-
libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma
--enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-
libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-
libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-
libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox
--enable-audiotoolbox --enable-neon
libavutil 59. 39.100 / 59. 39.100
libavcodec 61. 19.101 / 61. 19.101
libavformat 61. 7.100 / 61. 7.100
libavdevice 61. 3.100 / 61. 3.100
libavfilter 10. 4.100 / 10. 4.100
libswscale 8. 3.100 / 8. 3.100
libswresample 5. 3.100 / 5. 3.100
libpostproc 58. 3.100 / 58. 3.100
Input #0, ogg, from 'little-metadata.opus':
Duration: 00:03:31.71, start: 0.007500, bitrate: 119 kb/s
Stream #0:0(eng): Audio: opus, 48000 Hz, stereo, fltp
Metadata:
encoder : Lavf61.7.100
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Output #0, opus, to 'more-metadata.opus':
Metadata:
description : A good description
encoder : Lavf61.7.100
Stream #0:0(eng): Audio: opus, 48000 Hz, stereo, fltp
Metadata:
encoder : Lavf61.7.100
description : A good description
Press [q] to stop, [?] for help
[out#0/opus @ 0x600001c9c240] video:0KiB audio:3068KiB subtitle:0KiB other
streams:0KiB global headers:0KiB muxing overhead: 0.833101%
size= 3093KiB time=00:03:31.69 bitrate= 119.7kbits/s speed=7.67e+03x
$ ffprobe -show_entries stream_tags more-metadata.opus 2> /dev/null
[STREAM]
TAG:language=eng
TAG:encoder=Lavf61.7.100
TAG:comment=A good description
[/STREAM]
}}}
File info:
{{{
$ ffmpeg -v 9 -loglevel 99 -i little-metadata.opus
ffmpeg version 7.1.1 Copyright (c) 2000-2025 the FFmpeg developers
built with Apple clang version 15.0.0 (clang-1500.1.0.2.5)
configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/7.1.1_2 --enable-
shared --enable-pthreads --enable-version3 --cc=clang --host-cflags=
--host-ldflags='-Wl,-ld_classic' --enable-ffplay --enable-gnutls --enable-
gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-
libdav1d --enable-libharfbuzz --enable-libjxl --enable-libmp3lame
--enable-libopus --enable-librav1e --enable-librist --enable-librubberband
--enable-libsnappy --enable-libsrt --enable-libssh --enable-libsvtav1
--enable-libtesseract --enable-libtheora --enable-libvidstab --enable-
libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-
libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma
--enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-
libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-
libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-
libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox
--enable-audiotoolbox --enable-neon
libavutil 59. 39.100 / 59. 39.100
libavcodec 61. 19.101 / 61. 19.101
libavformat 61. 7.100 / 61. 7.100
libavdevice 61. 3.100 / 61. 3.100
libavfilter 10. 4.100 / 10. 4.100
libswscale 8. 3.100 / 8. 3.100
libswresample 5. 3.100 / 5. 3.100
libpostproc 58. 3.100 / 58. 3.100
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 'little-
metadata.opus'.
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 little-metadata.opus.
Successfully parsed a group of options.
Opening an input file: little-metadata.opus.
[AVFormatContext @ 0x1566054a0] Opening 'little-metadata.opus' for reading
[file @ 0x600000ece400] Setting default whitelist 'file,crypto,data'
Probing mp3 score:1 size:2048
Probing ogg score:100 size:2048
[ogg @ 0x1566054a0] Format ogg probed with size=2048 and score=100
[ogg @ 0x1566054a0] ogg_packet: curidx=-1
[ogg @ 0x1566054a0] ogg_packet: idx=0 pstart=0 psize=0 segp=0 nsegs=1
[ogg @ 0x1566054a0] ogg_packet: curidx=-1
[ogg @ 0x1566054a0] ogg_packet: idx=0 pstart=19 psize=0 segp=0 nsegs=1
[ogg @ 0x1566054a0] ogg_packet: curidx=-1
[ogg @ 0x1566054a0] ogg_packet: idx=0 pstart=87 psize=0 segp=0 nsegs=71
[ogg @ 0x1566054a0] found headers
[ogg @ 0x1566054a0] ogg_packet: curidx=-1
[ogg @ 0x1566054a0] ogg_packet: idx=0 pstart=0 psize=0 segp=0 nsegs=71
[ogg @ 0x1566054a0] Before avformat_find_stream_info() pos: 9179 bytes
read:130843 seeks:3 nb_streams:1
For transform of length 120, inverse, mdct_float, flags: [aligned,
out_of_place], found 5 matches:
1: mdct_pfa_15xM_inv_float_c - type: mdct_float, len: [30, ∞],
factors[2]: [15, any], flags: [unaligned, out_of_place, inv_only], prio:
304
2: mdct_pfa_5xM_inv_float_c - type: mdct_float, len: [10, ∞],
factors[2]: [5, any], flags: [unaligned, out_of_place, inv_only], prio:
144
3: mdct_pfa_3xM_inv_float_c - type: mdct_float, len: [6, ∞],
factors[2]: [3, any], flags: [unaligned, out_of_place, inv_only], prio:
112
4: mdct_inv_float_c - type: mdct_float, len: [2, ∞], factors[2]: [2,
any], flags: [unaligned, out_of_place, inv_only], prio: 96
5: mdct_naive_inv_float_c - type: mdct_float, len: [2, ∞], factors[2]:
[2, any], flags: [unaligned, out_of_place, inv_only], prio: -130976
For transform of length 4, inverse, fft_float, flags: [aligned, inplace,
preshuf], found 2 matches:
1: fft4_fwd_float_neon - type: fft_float, len: 4, factor: 2, flags:
[aligned, inplace, out_of_place, preshuf], prio: 352
2: fft4_ns_float_c - type: fft_float, len: 4, factor: 2, flags:
[unaligned, inplace, out_of_place, preshuf], prio: 96
Transform tree:
mdct_pfa_15xM_inv_float_c - type: mdct_float, len: 120, factors[2]:
[15, any], flags: [unaligned, out_of_place, inv_only]
fft4_fwd_float_neon - type: fft_float, len: 4, factor: 2, flags:
[aligned, inplace, out_of_place, preshuf]
For transform of length 240, inverse, mdct_float, flags: [aligned,
out_of_place], found 5 matches:
1: mdct_pfa_15xM_inv_float_c - type: mdct_float, len: [30, ∞],
factors[2]: [15, any], flags: [unaligned, out_of_place, inv_only], prio:
304
2: mdct_pfa_5xM_inv_float_c - type: mdct_float, len: [10, ∞],
factors[2]: [5, any], flags: [unaligned, out_of_place, inv_only], prio:
144
3: mdct_pfa_3xM_inv_float_c - type: mdct_float, len: [6, ∞],
factors[2]: [3, any], flags: [unaligned, out_of_place, inv_only], prio:
112
4: mdct_inv_float_c - type: mdct_float, len: [2, ∞], factors[2]: [2,
any], flags: [unaligned, out_of_place, inv_only], prio: 96
5: mdct_naive_inv_float_c - type: mdct_float, len: [2, ∞], factors[2]:
[2, any], flags: [unaligned, out_of_place, inv_only], prio: -130976
For transform of length 8, inverse, fft_float, flags: [aligned, inplace,
preshuf], found 3 matches:
1: fft8_ns_float_neon - type: fft_float, len: 8, factor: 2, flags:
[aligned, inplace, out_of_place, preshuf], prio: 352
2: fft_pfa_ns_float_c - type: fft_float, len: [6, ∞], factors[2]: [7,
5, 3, 2, any], flags: [unaligned, inplace, out_of_place, preshuf], prio:
112
3: fft8_ns_float_c - type: fft_float, len: 8, factor: 2, flags:
[unaligned, inplace, out_of_place, preshuf], prio: 96
Transform tree:
mdct_pfa_15xM_inv_float_c - type: mdct_float, len: 240, factors[2]:
[15, any], flags: [unaligned, out_of_place, inv_only]
fft8_ns_float_neon - type: fft_float, len: 8, factor: 2, flags:
[aligned, inplace, out_of_place, preshuf]
For transform of length 480, inverse, mdct_float, flags: [aligned,
out_of_place], found 5 matches:
1: mdct_pfa_15xM_inv_float_c - type: mdct_float, len: [30, ∞],
factors[2]: [15, any], flags: [unaligned, out_of_place, inv_only], prio:
304
2: mdct_pfa_5xM_inv_float_c - type: mdct_float, len: [10, ∞],
factors[2]: [5, any], flags: [unaligned, out_of_place, inv_only], prio:
144
3: mdct_pfa_3xM_inv_float_c - type: mdct_float, len: [6, ∞],
factors[2]: [3, any], flags: [unaligned, out_of_place, inv_only], prio:
112
4: mdct_inv_float_c - type: mdct_float, len: [2, ∞], factors[2]: [2,
any], flags: [unaligned, out_of_place, inv_only], prio: 96
5: mdct_naive_inv_float_c - type: mdct_float, len: [2, ∞], factors[2]:
[2, any], flags: [unaligned, out_of_place, inv_only], prio: -130976
For transform of length 16, inverse, fft_float, flags: [aligned, inplace,
preshuf], found 3 matches:
1: fft16_ns_float_neon - type: fft_float, len: 16, factor: 2, flags:
[aligned, inplace, out_of_place, preshuf], prio: 352
2: fft_pfa_ns_float_c - type: fft_float, len: [6, ∞], factors[2]: [7,
5, 3, 2, any], flags: [unaligned, inplace, out_of_place, preshuf], prio:
112
3: fft16_ns_float_c - type: fft_float, len: 16, factor: 2, flags:
[unaligned, inplace, out_of_place, preshuf], prio: 96
Transform tree:
mdct_pfa_15xM_inv_float_c - type: mdct_float, len: 480, factors[2]:
[15, any], flags: [unaligned, out_of_place, inv_only]
fft16_ns_float_neon - type: fft_float, len: 16, factor: 2, flags:
[aligned, inplace, out_of_place, preshuf]
For transform of length 960, inverse, mdct_float, flags: [aligned,
out_of_place], found 5 matches:
1: mdct_pfa_15xM_inv_float_c - type: mdct_float, len: [30, ∞],
factors[2]: [15, any], flags: [unaligned, out_of_place, inv_only], prio:
304
2: mdct_pfa_5xM_inv_float_c - type: mdct_float, len: [10, ∞],
factors[2]: [5, any], flags: [unaligned, out_of_place, inv_only], prio:
144
3: mdct_pfa_3xM_inv_float_c - type: mdct_float, len: [6, ∞],
factors[2]: [3, any], flags: [unaligned, out_of_place, inv_only], prio:
112
4: mdct_inv_float_c - type: mdct_float, len: [2, ∞], factors[2]: [2,
any], flags: [unaligned, out_of_place, inv_only], prio: 96
5: mdct_naive_inv_float_c - type: mdct_float, len: [2, ∞], factors[2]:
[2, any], flags: [unaligned, out_of_place, inv_only], prio: -130976
For transform of length 32, inverse, fft_float, flags: [aligned, inplace,
preshuf], found 3 matches:
1: fft32_ns_float_neon - type: fft_float, len: 32, factor: 2, flags:
[aligned, inplace, out_of_place, preshuf], prio: 352
2: fft_pfa_ns_float_c - type: fft_float, len: [6, ∞], factors[2]: [7,
5, 3, 2, any], flags: [unaligned, inplace, out_of_place, preshuf], prio:
112
3: fft32_ns_float_c - type: fft_float, len: 32, factor: 2, flags:
[unaligned, inplace, out_of_place, preshuf], prio: 96
Transform tree:
mdct_pfa_15xM_inv_float_c - type: mdct_float, len: 960, factors[2]:
[15, any], flags: [unaligned, out_of_place, inv_only]
fft32_ns_float_neon - type: fft_float, len: 32, factor: 2, flags:
[aligned, inplace, out_of_place, preshuf]
[ogg @ 0x1566054a0] ogg_packet: curidx=0
[ogg @ 0x1566054a0] ogg_packet: idx=0 pstart=87 psize=0 segp=0 nsegs=71
[opus @ 0x157804080] skip 312 / discard 0 samples due to side data
[opus @ 0x157804080] skip 312/960 samples
[ogg @ 0x1566054a0] All info found
[ogg @ 0x1566054a0] stream 0: start_time: 0.0075 duration: 211.7075
[ogg @ 0x1566054a0] format: start_time: 0.0075 duration: 211.7075
(estimate from stream) bitrate=119 kb/s
[ogg @ 0x1566054a0] After avformat_find_stream_info() pos: 9179 bytes
read:130843 seeks:3 frames:1
Input #0, ogg, from 'little-metadata.opus':
Duration: 00:03:31.71, start: 0.007500, bitrate: 119 kb/s
Stream #0:0(eng), 1, 1/48000: Audio: opus, 48000 Hz, stereo, fltp, delay
312
Metadata:
encoder : Lavf61.7.100
Successfully opened the file.
Correcting start time of Input #0 by 9223372036854768307 us.
At least one output file must be specified
[AVIOContext @ 0x1567041f0] Statistics: 130843 bytes read, 3 seeks
}}}
I think I traced down why:
This boils down to some field names being changed according to
`ff_vorbiscomment_metadata_conv` (`libavformat/vorbiscomment.c`).
If I understand the uses in `ogg_write_vorbiscomment`
(`libavformat/oggenc.c`) and `ff_vorbis_comment`
(`libavformat/oggparsevorbis.c`) correctly, during encoding the field name
`comment` becomes `DESCRIPTION` and during decoding `DESCRIPTION` becomes
`comment` again.
When looking at the code, the same should happen for flac.
This would mean that at least in the actual `more-metadata.opus` file the
fields have the correct name. Unfortunately I wasn't able to find a flag
to disable this nor any documentation about this conversion and would
therefore call it at least unintuitive if not misleading.
I think the conversion during encoding to be fine, since it converts
towards a standard. But I would expect `ffprobe` to show me what is
written in a file and this makes it impossible to know the actual field
name.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/11559>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
_______________________________________________
FFmpeg-trac mailing list
FFmpeg-trac@avcodec.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-trac
To unsubscribe, visit link above, or email
ffmpeg-trac-requ...@ffmpeg.org with subject "unsubscribe".
