[Ffmpeg-devel] raw video support in quicktime wrongly assumesraw audio

[Baptiste Coudurier]

Tomas Stenlund wrote:
>>> [...]
>>
>> Yes. Point is that 'hdlr' atom can be located after 'stsd' atom,
>> therefore codec type is not known while parsing 'stsd'.
> 
> In the Quicktime file format document they say:
> 
> -----8<----------8<-----------8<-----------8<----------8<-----------8<--------
> 
> Atoms within container atoms do not have to be in any particular order,
> with the exception of handler
> description atoms. Handler description atoms must come before their
> data. For example, the media
> handler description must come before a media information atom. A data
> handler description atom
> must come before a data information atom.
> -----8<----------8<-----------8<-----------8<----------8<-----------8<--------
> 
> 

hum, seems right for mov, however :
Quote from 14496-12, isom media (mp4/3gp):

2) It is strongly 'recommended' that all header boxes be placed first in
their container: these boxes are
   the Movie Header, Track Header, Media Header, and the specific media
headers inside the Media
   Information Box (e.g. the Video Media Header).

Strictly speaking, it is not mandatory, and I have at least one sample
where it comes after, and Quicktime reads it well.

> And they always show the layouts of the atoms and structures in a
> particular.
> I'm a bit confused here, what atoms are handler description atoms ? But
> I guess you are
> correct, that the order is not given and that it is better to be safe
> than sorry.
> 
>>
>> Solution is to delay 'stsd' parsing until we are sure about the codec
>> type. Im actually working on it.
>>
> 
> Reading in the entire moov structure or just that part ?

Just 'stsd' part. Anyway it seems that not overwriting codec_type might
be better than nothing. It will not be perfect though.

-- 
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