On Tue, 30 Apr 2013 17:19:21 +0200, Jindřich Makovička <[email protected]> 
wrote:
> On Mon, Apr 29, 2013 at 9:10 PM, Anton Khirnov <[email protected]> wrote:
> >
> > On Mon, 29 Apr 2013 12:10:50 +0200, Jindřich Makovička <[email protected]> 
> > wrote:
> >> Hi,
> >>
> >> this patch adds original and copyright flags from MPEG audio headers
> >> to AVFormatContext, so they can be displayed by avprobe.
> >>
> >> Could this feature be included in upstream? We encountered MPEG-PS
> >> sources that (ab)use the "original" flag to distinguish between
> >> original and dubbed audio, so it would come handy.
> >>
> >
> > I'm not against exposing this information in principle, but I don't like 
> > adding
> > a format-specific field to AVCodecContext. History shows that it doesn't 
> > lead to
> > anything good.
> >
> > I see two possible ways to expose this.
> > One is through decoder-private AVOptions, which contrary to the name can 
> > also be
> > used to retrieve values from opaque structs.
> 
> I tried this approach before realizing that avctx->priv_data is
> discarded by avcodec_close(), and unavailable after
> avformat_find_stream_info() anyway.
> 
> > Another is through newly added frame side data/metadata.
> 
> Is it acceptable to simply export the 32bit MPEG header as a side data?
> 

How is this better than simply looking at the first four bytes of the packet
data?

-- 
Anton Khirnov
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