[FFmpeg-devel] [PATCH] Correct ffplay timing of video after seek forward by 10 seconds when new seeking API used

Michael Niedermayer michaelni
Sat Jul 25 22:45:31 CEST 2009


On Sat, Jul 25, 2009 at 05:58:42PM +0200, Ivan Schreter wrote:
> Michael Niedermayer wrote:
>> On Sat, Jul 25, 2009 at 02:44:32PM +0200, Ivan Schreter wrote:
>>   
>>> [...]
>>> The attached trivial patch reduces the maximum frame time to 5 seconds, 
>>> which fixes the problem for this particular case of (inexact) seeking of 
>>> 10 seconds into future.
>>>
>>> OK to apply?
>>>     
>> [...]
>>> However, someone should fix it correctly for seek case, but I don't get 
>>> the     
>>
>> as you say "someone should fix it correctly" i guess i dont need to
>> explain why your patch is wrong you seem to already know 
>>   
> Ehm, it's not "wrong". It happens it's not a proper solution. It's just a 
> workaround to alleviate the problem. But it doesn't change readability of 
> the code or otherwise interfere - it's just a change of one wildly-chosen 
> constant (actually, quite badly chosen, given 10 second step for seeking).

good then ill elaborate
your change will break playback of files that have frames with duration >5sec
i have some old msmpeg4 avis that contain several second long frames
and not every contstant has been wildly choosen


>>   
>>> code 100%, so I didn't want to create more problems than to fix...
>>>     
>>
>> and yes ffplays timing code is tricky and not even 100% bugfree, for 
>> example
>> i think theres a little issue with timestamps or durations being applied 
>> to
>> th next or previus frame by mistake ...
>>
>>   
> I tried for a proper quick fix, but as you write, it looks like frame 
> timings are shifted by one frame, thus it doesn't help just to change delay 
> computation of one frame after seek (or reset timing after seek) - it's the 
> second frame, which hangs.
>
> I don't have time for a proper fix, since I'd rather make sure other stuff 
> works well (especially seeking for relevant formats for video editing). 
> ffplay is in my eyes just a toy tool (or proof of concept how a player can 
> be written with FFmpeg). Or am I mistaken there?

whatever it is, please do not break it with random hacks you want for
todays work.


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No human being will ever know the Truth, for even if they happen to say it
by chance, they would not even known they had done so. -- Xenophanes
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