[FFmpeg-user] File metadata in m4a causing player problem?
ajebay at errichel.co.uk
Tue Oct 22 19:49:31 EEST 2019
On 22/10/2019 16:57, Budge wrote:
> On 21/10/2019 09:28, Moritz Barsnick wrote:
>> Hi Budgie,
>> On Sun, Oct 20, 2019 at 09:56:40 +0100, Budge wrote:
>>> I have a set of m4a audio files which I can play but on which the
>>> progress bar does not work. If I select anywhere along the progress bar
>>> playing starts again from the beginning.
>> In which players does seeking not work? In all of them? Which did you
>> How were there files created? Are they arbitrary files, or did you
>> create them with ffmpeg?
>> Can you provide some of these files?
>>> The only difference I can see when using ffprobe to examine the metadata
>>> is that files which have a creation_time set have a non functioning
>>> progress bar problem.
>> That may be a symptom of their creation, but not the actual root cause
>> for your issues.
>>> What I wish to do is remove the tag:
>>> creation_time : 1970-01-01T00:00:00.000000Z
>> ffmpeg certainly didn't create this by itself, but I understand that's
>> not what you're trying to say. ;-)
>>> I confess using ffmpeg to achieve this, if indeed this is the correct
>>> tool, is well beyond my ability and I am seeking help here.
>> Even though I don't believe that is the root cause, I was going to explain
>> to you how to strip metadata using ffmpeg. But it turns out that, when
>> remuxing, ffmpeg doesn't actually copy the creation_time. So all you
>> have to do may be:
>> $ ffmpeg -i input.m4a -c copy output.m4a
>> You can then test the output file.
>> The resulting file may also be fixed for other reasons than the
>> metadata, e.g. reconstruction of some index or something like that,
>> which the original may be missing. (Guessing here - just go try.)
>> Hope this helps,
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>> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".
> Hi and very many thanks for the detailed reply.
> I obtained the file from BBC using get_iplayer, one of several and years
> ago. I believe the problem resulted from my poor workmanship when, while
> upgrading my workstation, I failed to install AtomicParsley. (Running
> on 64 bit system with openSUSE but cannot recall version.)
> As a result the files would not play on the Linn DS until I moved the
> moov atom to the start of the file metadata using qt-faststart but
> otherwise I believe the tags were intact. The files then played OK but
> the progress bar problem was present.
> I can let you have samples of good and bad files for comparison but they
> are quite big so need your advice how to get them to you. I can use
> Dropbox and send a link if this would be OK.
> The problem only occurs with my Linn DS devices. I am using BubbleDS on
> Samsung S6 Android phone as control point and minimserver on Qnap NAS as
> media server.
> On another player such as a RaspberryPi with Raspbian OS
> and IQaudio PiDAC etc and Upmpdcli the progress bar works as it should.
> AFAIK get_iplayer uses ffmpeg when downloading but I am not a coder so
> cannot comment further.
> In the light of your advice above there may be other criteria to examine
> in the file as;
> None of the files I have which do NOT have the creation_time tag work
> Only those files which still have the creation_time tag have a problem with
> the Linn DS devices.
> Meanwhile I will try your suggestion and report progress.
> Many thanks once more.
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".
Just a follow up trying to run file through ffmpeg as you suggested the
file now does not play and BubbleDS moves to next file in playlist or
If you have time I would appreciate your examination of the samples.
Let me know.
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