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

Rostislav Pehlivanov atomnuker at gmail.com
Tue May 15 19:15:05 EEST 2018


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 at 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.
> _______________________________________________
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>

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.
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.


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