[FFmpeg-devel] [PATCH v6 1/3] avcodec: add flags for packets with top/bottom field

[Rostislav Pehlivanov]

On 15 May 2018 at 18:03, wm4 <nfxjfg at googlemail.com> wrote:

> On Tue, 15 May 2018 17:15:05 +0100
> Rostislav Pehlivanov <atomnuker at gmail.com> wrote:
>
> > On 15 May 2018 at 15:55, wm4 <nfxjfg at googlemail.com> wrote:
> >
> > > On Mon, 14 May 2018 18:26:35 -0400
> > > Patrick Keroulas <patrick.keroulas at savoirfairelinux.com> wrote:
> > >
> > > > Signed-off-by: Patrick Keroulas <patrick.keroulas@
> savoirfairelinux.com>
> > > > ---
> > > >  doc/APIchanges       | 3 +++
> > > >  libavcodec/avcodec.h | 8 ++++++++
> > > >  libavcodec/version.h | 4 ++--
> > > >  3 files changed, 13 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/doc/APIchanges b/doc/APIchanges
> > > > index bbefc83..d06868e 100644
> > > > --- a/doc/APIchanges
> > > > +++ b/doc/APIchanges
> > > > @@ -15,6 +15,9 @@ libavutil:     2017-10-21
> > > >
> > > >  API changes, most recent first:
> > > >
> > > > +2018-05-xx - xxxxxxxxxx - lavc 58.20.100 - avcodec.h
> > > > +  Add AV_PKT_FLAG_TOP_FIELD and AV_PKT_FLAG_BOTTOM_FIELD.
> > > > +
> > > >  2018-05-xx - xxxxxxxxxx - lavu 56.18.101 - hwcontext_cuda.h
> > > >    Add AVCUDADeviceContext.stream.
> > > >
> > > > diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> > > > index fb0c6fa..14811be 100644
> > > > --- a/libavcodec/avcodec.h
> > > > +++ b/libavcodec/avcodec.h
> > > > @@ -1480,6 +1480,14 @@ typedef struct AVPacket {
> > > >   */
> > > >  #define AV_PKT_FLAG_DISPOSABLE 0x0010
> > > >
> > > > +/**
> > > > + * The packet contains a top field.
> > > > + */
> > > > +#define AV_PKT_FLAG_TOP_FIELD  0x0020
> > > > +/**
> > > > + * The packet contains a bottom field.
> > > > + */
> > > > +#define AV_PKT_FLAG_BOTTOM_FIELD  0x0040
> > > >
> > > >  enum AVSideDataParamChangeFlags {
> > > >      AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT  = 0x0001,
> > > > diff --git a/libavcodec/version.h b/libavcodec/version.h
> > > > index 3fda743..b9752ce 100644
> > > > --- a/libavcodec/version.h
> > > > +++ b/libavcodec/version.h
> > > > @@ -28,8 +28,8 @@
> > > >  #include "libavutil/version.h"
> > > >
> > > >  #define LIBAVCODEC_VERSION_MAJOR  58
> > > > -#define LIBAVCODEC_VERSION_MINOR  19
> > > > -#define LIBAVCODEC_VERSION_MICRO 101
> > > > +#define LIBAVCODEC_VERSION_MINOR  20
> > > > +#define LIBAVCODEC_VERSION_MICRO 100
> > > >
> > > >  #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR,
>
> > > \
> > > >
> > >  LIBAVCODEC_VERSION_MINOR, \
> > >
> > > So far we could avoid codec-specific packet flags, and I think it
> > > should stay this way. Maybe make it side data, something with naming
> > > specific to the bitpacked codec. Or alternatively, if this codec
> > > is 100% RTP specific and there's no such thing as standard bitpacked
> > > packets (e.g. muxed in other files etc.), add it to the packet
> > > directly. The RTP code "repacks" it already on the libavformat side
> > > anyway.
> > > _______________________________________________
> > > ffmpeg-devel mailing list
> > > ffmpeg-devel at ffmpeg.org
> > > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > >
> >
> > This codec isn't RTP specific, its the same as V210. There are no flags
> in
> > the bitstream, its just a sequence of packed pixels. And just like v210
> > there's a standard for what packets need to look like (rfc4175, and
> > unfortunately it does specify the fields need to be separate), so
> packing 2
> > fields in the muxer isn't really an option.
>
> Then why are there separate bitpacked and v210 decoders/codec_ids?
>

Its a different type of packing.



> > Side data seems a bit of an overkill for a flag. I'd say the field flags
> > are not codec specific as some raw codecs and containers can signal
> fields
> > per packet. So I don't really mind them.
>
> You want codec specific flags to accumulate in AVPacket.flags? Can't way
> until we change the flags field to int128_t.
>
>
No, but I think 2 more bits won't hurt much, especially considering pretty
much all formats supporting interlaced content split each field into a
separate packet.