[FFmpeg-devel] [PATCH 4/4] avformat/concatdec: always re-calculate start time and duration

Marton Balint cus at passwd.hu
Thu Dec 13 23:09:55 EET 2018

On Thu, 13 Dec 2018, Nicolas George wrote:

> Marton Balint (2018-12-09):
>> Seeking will only work in the special case I provided in the commit message,
>> when we always seek back to the beginning and otherwise read the referenced
>> files continously.
>> In theory, when we are in "seekable" state then if we detect a duration
>> change we could indeed update all subsequent start times to provide proper
>> timestamps for seeking, but I did not need this for my purpose, and I am not
>> sure if it's worth the extra code needed.
> I am really not comfortable with leaving the loaded gun of the seekable
> flag if it does not work reliably. I think at the very least the code
> should detect a file change, emit a warning and invalidate all
> subsequent durations.
> Note that if all you are interested in is seeking to the beginning of
> the virtual file, it can always work. I would not object to a special
> case in the seek code for that.

I can do this to replace the functionality of the first patch in the 
series. However, this patch (4/4) is still going to be needed, but the 
context will not be seekable anymore (except for seeking into start). Is 
this acceptable?


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