The PBCore metadata class [1] has the indexed essence track properties defined
as:
public static Property ESSENCE_TRACK_TYPE(int index)
{
return getIndexedEssenceTrackProperty(index, "essenceTrackType");
}
which resolve via:
protected static Property getIndexedEssenceTrackProperty(int index, String
elementName)
{
return Property.internalText(
MessageFormat.format(ELEMENT_INSTANTIATION_ESSENCE_TRACK_FORMAT, index) +
PREFIX_PBCORE + Metadata.NAMESPACE_PREFIX_DELIMITER +
elementName);
}
so in your example, setting a value of Audio on two essence tracks would
currently look like:
metadata.set(PBCore.ESSENCE_TRACK_TYPE(0), "Audio");
metadata.set(PBCore.ESSENCE_TRACK_TYPE(1), "Audio");
That index related component could potentially live in the Metadata class
itself but if we choose to support multiple levels of structured properties,
i.e.:
company[1]/contact[0]/phoneNumber[2]=555-1234
that might prove difficult to support.
Regards,
Ray
[1]
https://github.com/AlfrescoLabs/tika-ffmpeg/blob/master/src/main/java/org/apache/tika/metadata/PBCore.java
On August 7, 2014 at 6:21:37 AM, Nick Burch ([email protected]) wrote:
> On Wed, 6 Aug 2014, Ray Gauss wrote:
> > I've updated tika-ffmpeg with a new file with 2 audio tracks and a
> > subtitle track and added a test. The metadata looks as follows:
> >
> > pbcore:instantiationDataRate=3511 kb/s
> > pbcore:instantiationDuration=00:00:01.03
> > pbcore:instantiationEssenceTrack[0]/pbcore:essenceTrackType=Video
> > pbcore:instantiationEssenceTrack[0]/pbcore:essenceTrackFrameSize=480x270
> > pbcore:instantiationEssenceTrack[0]/pbcore:essenceTrackFrameRate=29.97
> fps
> > pbcore:instantiationEssenceTrack[0]/pbcore:essenceTrackDataRate=360 kb/s
> > pbcore:instantiationEssenceTrack[0]/pbcore:essenceTrackEncoding=h264
> > pbcore:instantiationEssenceTrack[0]/pbcore:essenceTrackLanguage=eng
> > pbcore:instantiationEssenceTrack[1]/pbcore:essenceTrackType=Audio
> > pbcore:instantiationEssenceTrack[1]/pbcore:essenceTrackSamplingRate=48000
> Hz
>
> This actually looks better than I'd expected, so I have fewer resistances
> now than before
>
> > A much more concise representation would be:
> >
> > Iptc4xmpExt:LocationCreated/Iptc4xmpExt:City
> > Iptc4xmpExt:LocationCreated/Iptc4xmpExt:CountryName
> > ...
> > Iptc4xmpExt:LocationShown[0]/Iptc4xmpExt:City
> > Iptc4xmpExt:LocationShown[0]/Iptc4xmpExt:CountryName
>
> This looks ok-ish to me too
>
>
> One thing that I am wondering about though:
>
> > pbcore:instantiationDataRate=3511 kb/s
> > pbcore:instantiationDuration=00:00:01.03
> > stream[0]/pbcore:essenceTrackType=Video
> > stream[0]/pbcore:essenceTrackFrameSize=480x270
> > stream[0]/pbcore:essenceTrackFrameRate=29.97 fps
> > stream[1]/pbcore:essenceTrackType=Audio
> > stream[1]/pbcore:essenceTrackSamplingRate=48000 Hz
>
> I can see how we can farily easily modify Metadata to accept an optional
> stream number when setting key/values, which would automatically prefix
> them with stream[number]/
>
> For a property like pbcore:essenceTrackType, and your alternate scheme,
> how would you see the method on Metadata look like to set a
> pbcore:essenceTrackType to a value of Audio on two different tracks?
>
> Nick
