[FFmpeg-devel] [mpegaudio_parser] Skip trailing junk data when flushing parser.

Dale Curtis dalecurtis at chromium.org
Thu Mar 1 02:17:52 EET 2018

On Mon, Feb 26, 2018 at 3:07 PM, Michael Niedermayer <michael at niedermayer.cc
> wrote:
> The way parsers are intended to work (that is years ago and i dont remember
> that there was a proposal to change this)
> is to never drop data. Thats how the stuff was intended to work.
> On top of that it was sometimes convenient to just drop data in a Parser,
> or
> a Parser was sloppy implemented and unintentionally looses data.
> To awnser the above question, i dont think the mp3 parser can just be
> changed
> alone. As other code like for example muxers depend on some tags being
> discarded.
> So any change has to be done with some care.
> not specific to just mp3 but all parsers,
> droping data the parser does not understand is bad though.
> it can be an extension that some decoders could use
> it can be damaged data that a decoder can partly recover and improve the
> output
> it can be some data that is invalid in that location (like midstream
> metadata
> changes in some formats) but that still contains valuable data and that
> would
> be lost even if the components downstream in a player are able to
> interpret it.
> Thus for me droping data in a parser is something that i prefer to avoid.
> Unless "not droping" would cause noticably more problems ...
Thanks for the information. I agree that seems reasonable, but is a
significant API change to the current system that, as you note, extends
beyond just the mp3 parser. It's certainly outside of the scope of things I
can sign up for at this time. While I feel my patch is a strict improvement
(more consistent) that fits with the current design, we can maintain this
in Chromium if you'd rather not accept it.

- dale

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