\\ 'separator' in id3tag causes unwanted truncation of ffprobe output

[ginjaninja]

Summary of the bug: ffprobe truncates artist (possibly others as well) tag of mp3/flac file, if it contains '
' text 'separator' eg. 'artist1
artist2
artist3' outputs as 'artist3'
How to reproduce: amend artist tag of mp3 or flac file as 'artist1
artist2
artist3'; run ffprobe against it and review output.

C:\New folder>ffprobe.exe "01. Ring Ring.flac"
ffprobe version N-56041-gf974289 Copyright (c) 2007-2013 the FFmpeg developers

built on Sep 4 2013 18:01:17 with gcc 4.7.3 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av

isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetyp
e --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --ena
ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libsp
eex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-
amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --
enable-libxvid --enable-zlib

libavutil 52. 43.100 / 52. 43.100
libavcodec 55. 31.101 / 55. 31.101
libavformat 55. 16.101 / 55. 16.101
libavdevice 55. 3.100 / 55. 3.100
libavfilter 3. 83.102 / 3. 83.102
libswscale 2. 5.100 / 2. 5.100
libswresample 0. 17.103 / 0. 17.103
libpostproc 52. 3.100 / 52. 3.100

Input #0, flac, from '01. Ring Ring.flac':

Metadata:

ALBUM : Ring Ring
ARTIST : artist3
GENRE : Pop
TITLE : Ring Ring
album_artist : aartist1/aartist2/aartist3
DATE : 1973
track : 1

Duration: 00:03:04.87, bitrate: 1021 kb/s

Stream #0:0: Audio: flac, 44100 Hz, stereo, s16

[ginjaninja]

artist1\\artist2\\artist3 outputs as artist3

[ginjaninja]

didnt escape the \\ in the original post

[Carl Eugen Hoyos]

Is this not reproducible with ffmpeg (the application)?

[ginjaninja]

yes ffmpeg also truncates artist tag if it contains \\

C:\New folder>ffmpeg.exe -v 99 -i "01. Ring Ring.flac" test.mp3
ffmpeg version N-57057-g024bf3a Copyright (c) 2000-2013 the FFmpeg developers
  built on Oct 11 2013 18:01:59 with gcc 4.8.1 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetyp
e --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --ena
ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libsp
eex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aa
cenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavp
ack --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  libavutil      52. 46.101 / 52. 46.101
  libavcodec     55. 35.100 / 55. 35.100
  libavformat    55. 19.100 / 55. 19.100
  libavdevice    55.  4.100 / 55.  4.100
  libavfilter     3. 88.101 /  3. 88.101
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 17.103 /  0. 17.103
  libpostproc    52.  3.100 / 52.  3.100
Splitting the commandline.
Reading option '-v' ... matched as option 'v' (set logging level) with argument
'99'.
Reading option '-i' ... matched as input file with argument '01. Ring Ring.flac'
.
Reading option 'test.mp3' ... matched as output file.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option v (set logging level) with argument 99.
Successfully parsed a group of options.
Parsing a group of options: input file 01. Ring Ring.flac.
Successfully parsed a group of options.
Opening an input file: 01. Ring Ring.flac.
[flac @ 0254a000] Format flac probed with size=2048 and score=50
[flac @ 0254a000] File position before avformat_find_stream_info() is 8628
[flac @ 0242ebe0] sample/frame number mismatch in adjacent frames
    Last message repeated 126 times
[flac @ 0254a000] max_analyze_duration 5000000 reached at 5015510 microseconds
[flac @ 0254a000] File position after avformat_find_stream_info() is 745472
Input #0, flac, from '01. Ring Ring.flac':
  Metadata:
    ALBUM           : Ring Ring
    ARTIST          : artist3
    GENRE           : Pop
    TITLE           : Ring Ring
    album_artist    : aartist1/aartist2/aartist3
    DATE            : 1973
    track           : 1
  Duration: 00:03:04.87, bitrate: 1021 kb/s
    Stream #0:0, 56, 1/44100: Audio: flac, 44100 Hz, stereo, s16
Successfully opened the file.

[Carl Eugen Hoyos]

Please upload a short sample.

[ginjaninja]

5 second clip, by way of example (less than 2.5mb limit)

[ginjaninja]

From another post i now realise that \\ is treated as special by mp3tag (the client i use to write tags). I had thought it was just a.n.other text string, but it turns out that \\ actually instructs mp3tag to write something special to the header.

for flacs the header (when viewed in hex editor) has artist=artist1....artist=artist2....artist=artist3
so ffmpeg isn't truncating a text string past the last \\, it is perhaps just not multi-value aware.

for mp3 the header is TPE1 artist1[00][00][00]artist2[00][00][00]artist3
and ffmpeg\ffprobe reports artist as artist1 (ie doesnt read past the 1st null character?)

so perhaps there is no standard for ffmpeg to accommodate? perhaps it is a peculiarity of the mp3tag client and the way it writes headers. Still it would be great if ffmpeg did support such headers by using its own format for output of multi value tags.

I understand other clients do write headers in a similar way. If the user could specify the text character to use to delimit the output for eg a multivalue artist field (such as the way they are written here by mp3tag), then my client would be able to see multiple artists as they were intended (it uses ffmpeg (ffprobe) to extract tags from files). My client could parse the output of ffmpeg (ffprobe) with the known separator to derive the multiple artists.

more universally, when using ffmpeg to transcode content, maybe if ffmpeg had an appreciation of these types of multi value headers, it could ensure they are written to the destination in the same format?

[Michael Niedermayer]

ffmpeg displays

ARTIST : artist1;artist2;artist3

now, dont remeber which commit fixed it

[Carl Eugen Hoyos]

Fixed by Ben Boeckel in 0dc66553

[ginjaninja]

multiple value appreciation is not working in ffprobe/ffmpeg version N-65895-g96b2ba6 for mp3s...It is working for flacs.

[ginjaninja]

mp3 file showing
\ not working

[ginjaninja]

still doesnt work for mp3s
​http://emby.media/community/index.php?/topic/25919-question-about-my-artist-tags/?p=254967