[FFmpeg-devel] [PATCH 7/7] lavf/mxfdec: add -field_rate option

[Michael Niedermayer]

On Thu, Mar 28, 2013 at 05:15:28PM +0100, Matthieu Bouron wrote:
> On Thu, Mar 28, 2013 at 04:37:10PM +0100, Michael Niedermayer wrote:
> > On Thu, Mar 28, 2013 at 03:41:51PM +0100, Matthieu Bouron wrote:
> > > Interpret sample rate as field rate for j2k codec with separate fields
> > > or segmented frame layout.
> > > 
> > > This option is required to obtain a correct frame rate since S422M
> > > specifies that the track sample rate could either be the frame rate
> > > or the field rate for separate field layout.
> > > 
> > 
> > > For segmented frame layout, the track sample rate is supposed to be the
> > > frame rate however some sample seems to use it as the field rate.
> > 
> > are you sure theres no way to distingish them automatically ?
> > file duration fields?
> > encoder name?
> > muxer name?
> > ...
> > 
> 
> AFAIK there is no mandatory information that can be used to interpret correctly
> the sample rate.
> 
> Based on the few samples i have:
>   - the one provided on ffmpeg trac (ntsc2.mxf): sample rate is frame
>     rate,
>   - the files issued by SAMMA systems: sample rate is field rate,
>   - the files issued by Canopus Co. systems: sample rate is field rate.
> 
> Maybe i could use the application_supplier_name from the mxf
> identification item to set a default behaviour ?

yes, its maybe a bit trial and error but IMHO its worth a try to set
it automatically


> 
> For reference, page 5 of http://www.digitizationguidelines.gov/guidelines/FADGI_MXF_ASAP_Issues_20110815.pdf
> 
> Matthieu
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-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The educated differ from the uneducated as much as the living from the
dead. -- Aristotle 
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