[FFmpeg-user] Missing "fiel" Video Sample Description extension in .mov's

Tim Nicholson nichot20 at yahoo.com
Fri Oct 5 12:09:03 CEST 2012


On 05/10/12 01:02, Carl Eugen Hoyos wrote:
> Tim Nicholson <nichot20 <at> yahoo.com> writes:
> 
>> From a perusal of the code in mov.c this is extracted to
>> st->codec->field_order with an AV_LOG_ERROR for unknown values
>> (AV_FIELD_UNKNOWN).
>>
>> Since I am not seeing that error I presume it is being successfully
>> retrieved.
>>
>> However in movenc.c the "fiel" extension is written provided that:-
>>
>> track->enc->field_order != AV_FIELD_UNKNOWN
>>
>> and since it is not being written I must assume that the above test is true.
>>
>> It would therefore seem that track->enc->field_order is not being set
>> from st->codec->field_order except in the case of a stream copy.
> 
> Could you use some printf's (don't forget to #undef printf) 
> to find out if your conclusion is actually correct?
> 

I have been doing that, and yes the value of track->enc->field_order is
0, I am now adding some more in suitable places to try and see what is
going on and where the value gets lost.

As far as I can see the reason that it works for the stream copy case is
that the information is carried over as part of a memcpy of extradata.

> Carl Eugen
> 
> [...]


-- 
Tim




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