[FFmpeg-devel] Query regarding codec parsers

[Carl Eugen Hoyos]

Am Mo., 13. Apr. 2020 um 17:27 Uhr schrieb Gautam Ramakrishnan
<gautamramk at gmail.com>:
>
> On Sun, Mar 29, 2020 at 8:34 PM Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> >
> > Am So., 29. März 2020 um 16:45 Uhr schrieb Gautam Ramakrishnan
> > <gautamramk at gmail.com>:
> >
> > > > > What exactly does a parser do and how is it different from a decoder?
> > > > > I am unable to understand the exact use case of a parser.
> > > >
> > > > Try the following:
> > > > $ cat 1.jpg 2.jpg | ffmpeg -i -f null -
> > > > (Is expected to decode two frames as can be seen in the console output,
> > > > also works for example with png)
> > > >
> > > > $ cat 1.j2k 2.j2k | ffmpeg -i - -f null -
> > > > Will only decode one frame because there is no parser to split the
> > > > input.
> > > >
> > > So does it basically try to find the SOC marker and EOC markers and
> > > split the streams into frames?
> >
> > Basically, yes.
> > Look at existing parsers in libavcodec/*parser* (or git grep AVCodecParser),
> > especially the jpeg parser.

> Would working on a parser be a good idea now?

Either that or you look at ticket #4681 (no idea how difficult this is).

Carl Eugen