[FFmpeg-devel] [PATCH] flv set pts

[Baptiste Coudurier]

Michael Niedermayer wrote:
> On Tue, Sep 30, 2008 at 01:02:53PM -0700, Baptiste Coudurier wrote:
>> Michael Niedermayer wrote:
>>> On Tue, Sep 30, 2008 at 12:00:59PM -0700, Baptiste Coudurier wrote:
>>>> Michael Niedermayer wrote:
>>>>> On Tue, Sep 30, 2008 at 11:28:45AM -0700, Baptiste Coudurier wrote:
>>>>>> Hi,
>>>>>>
>>>>>> Michael Niedermayer wrote:
>>>>>>> On Mon, Sep 29, 2008 at 07:56:17PM -0700, Baptiste Coudurier wrote:
>>>>>>>> Baptiste Coudurier wrote:
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> $subject.
>>>>>>>>>
>>>>>>>> Scratch old patch, this one should be correct.
>>>>>>> can you post some example input&output pts & dts values for some file
>>>>>>> with b frames.
>>>>>>> I suspicion would be that the patch is not completely correct but this
>>>>>>> should be more obvious from a list of timestamps and frame types.
>>>>>>>
>>>>>> Well, I didn't find any having < 0 cts yet, however it has been said
>>>>>> that cts is signed like in .mov, so code is assuming that.
>>>>>>
>>>>>> Files generated by FFmpeg does not have < 0 cts.
>>>>>>
>>>>>> Patch is doing the same as the .mov demuxer excepts that we cannot know
>>>>>> in advance while we can in .mov, though it misses has_b_frames = 1, I
>>>>>> can see, not harmful though.
>>>>>>
>>>>>> What do you think could be wrong ? I'll try to find a file in the mean time.
>>>>> Well
>>>>> if we take as example normal mpeg2 style IPB then
>>>>>         IPBBPBB
>>>>> dts:    0123456
>>>>> pts:    1423756
>>>>> would be correct
>>>>>
>>>>> now if dts where increased by one:
>>>>>
>>>>>         IPBBPBB
>>>>> dts:    1234567
>>>>> pts:    1423756
>>>>>
>>>>> then this would be wrong, and not only the ones for the B frames
>>>>> would be wrong but all would be. That is for example if the I frame
>>>>> is feeded at time 1 into the decoder then it will be output at time 2 not 1.
>>>>>
>>>> Humm of course yes, and in your situation, cts will be -1 for the third
>>>> frame to achieve dts 3 and pts 2, I don't see what you mean, the check
>>>> is indeed for cts < 0.
>>> well, i think the demuxer would output:
>>>
>>> dts:    12-----
>>> pts:    1423756
>>>
>>> but this is wrong for the first 2 frames
>>>
>> Yes, that is true, what can we do about that ?
>> It's sad not to set pts for correct files, what do you suggest ?
> 
> iam fine with the patch if it also prints some warning that the past
> timestamps might have been wrong

Patch updated.

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
Key fingerprint                 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA
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