[FFmpeg-devel] [PATCH]lavf/spdifenc: Automatically insert truehd_core bitstream filter

Hendrik Leppkes h.leppkes at gmail.com
Wed Feb 13 01:47:50 EET 2019

On Tue, Feb 12, 2019 at 12:54 PM Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> 2019-02-12 12:37 GMT+01:00, Hendrik Leppkes <h.leppkes at gmail.com>:
> > On Tue, Feb 12, 2019 at 12:28 PM Carl Eugen Hoyos <ceffmpeg at gmail.com>
> > wrote:
> >>
> >> Hi!
> >>
> >> Attached patch intends to fix ticket #7731.
> >
> > This is not a fix. The vast majority of TrueHD Atmos tracks work just
> > fine with the current limitations, and would needlessly drop the Atmos
> > information for every stream.
> Is it possible to detect if the Atmos core has to be dropped?

Not beforehand, since the size of future frames is of course unknown,
and there are no indications in the bitstream.
One could consider starting to drop Atmos data after it happened once,
but it'll probably still glitch out audio at that point.

Ideally the truehd spdif muxer should be revised to support a more
flexible buffering model, but its a tad bit complicated with the way
the spdif muxer is setup, and I've only recently learned myself how
its presumably supposed to be done, since the specifications are not
openly available.

- Hendrik

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