[FFmpeg-devel] [PATCH] write AC-3 metadata

[Anssi Hannula]

On 31.12.2010 15:31, Kieran Kunhya wrote:
>> clean effects ? This field indicates that the referenced
>> program element has no language.
>> hearing impaired ? This field indicates that the
>> referenced program element is prepared for the hearing
>> impaired.
>> visual_impaired_commentary ? This field indicates that the
>> referenced program element is prepared for the visually
>> impaired viewer.
>> [...]
> 
> For what it's worth, I've never seen anyone use anything other
> than "undefined" for that field in MPEG-2 systems. Visual Impaired
> commentary uses the country code "NAR" over here in the UK.

Here in Finland visual impaired commentary is marked correctly using
that field (additionally it has the country code "hun").

Also, somewhat relatedly, some channels (eurosport mainly, at least when
I last checked) are broadcast with mono audio encoded as 2 channels of a
single stream and therefore there are multiple language tags present per
stream.

I had some patches handling both the type field and multiple lang tags
in "Handling dual language mono audio encoded as stereo" thread earlier
this year (Feb and Jul), but I haven't had the time to revisit and
finish them (I plan to, but I won't make any promises; maybe after all
this dts/spdif stuff).

> AC-3 metadata can be placed in AAC through "Dolby Pulse" but we
> don't have any samples to see how that's done.


-- 
Anssi Hannula