[FFmpeg-user] id3 tags not really removed?

[Rodolfo Medina]

Rodolfo Medina <rodolfo.medina at gmail.com> writes:

> Moritz Barsnick <barsnick at gmx.net> writes:
>
>> On Wed, May 31, 2017 at 13:10:18 +0200, Cley Faye wrote:
>>> A shot in the dark here since I didn't have the patience to look at how
>>> -write_id3v1 work; but if I remember correctly, id3v1 tags are actually
>>> appended at the end of the mp3 stream in such a way that some older player
>>> would even play them, causing a small burst of audio at the end of such
>>> file.
>>> 
>>> If ffmpeg really doesn't handle them when reading the stream, it would
>>> explain why 1- they get copied during stream copy, 2- why older tag would
>>> still show up first, and maybe also 3- why the new tag would show up after
>>> initial playing of the file, if the reader actually move from the end of
>>> the file to detect them after reading.
>>
>> That was my assumption, and why I suggested using the additional option. But
>>I have had enough of shooting in the dark. I created a file with both v1 and
>>v2 ID3 tags: $ ffmpeg -f lavfi -i anoisesrc -c:a libmp3lame -metadata
>>title='Where is this found?' -write_id3v1 1 -t 1 -ac:a 1 -b:a 24k
>>tmp/id3tagtest.mp3
>>
>> and converted it in three different ways: $ ffmpeg -i tmp/id3tagtest.mp3
>> -metadata title='This is the new tag!' -c copy
>> tmp/id3tagtest_copied_and_new_matadate_no_explicit_id3v1.mp3 $ ffmpeg -i
>> tmp/id3tagtest.mp3 -write_id3v1 1 -metadata title='This is the new tag!' -c
>> copy tmp/id3tagtest_copied_and_new_matadate_explicit_id3v1.mp3 $ ffmpeg -i
>> tmp/id3tagtest.mp3 -map_metadata -1 -c copy
>> tmp/id3tagtest_copied_and_map_metadata_minus_1.mp3
>>
>> and apparently ffmpeg *always* overwrites or at least deletes the old
>> ID3v1 tag. None of the three resulting files contained a leak of the
>> old tag. (Inspected with "strings".) Period, 'nuff said.
>>
>> So, unless I missed something, it's the player's fault.
>
>
> It seems so.  Sorry for having engaged people in a problem that does not
> concern ffmpeg.  Now I changed not only tags, but also file names and the
> player still sees old file names.  When I click over them to listen to them,
> another song is played in place of them.  It's sort of been crazy (after
> having driven *me* crazy! ;-) ).


...then, after a while, say some hours, it suddenly detects the changes and
shows the right new file names and tags.  So it seems that Moritz was right
when speaking of some sort of `cache' my mplayer is doing...

Rodolfo