On 20/06/2019 00:45, Andreas Rheinhardt wrote:
> If any of the *_metadata filter based upon cbs currently updates a video
> codec parameter like color information, the AVCodecParameters are not
> updated accordingly, so that e.g. muxers write header values based upon
> outdated information that may precede and thereby nullify the new values
> on the bitstream level.
> This commit adds a function to also update the video codec parameters
> so that the above situation can be fixed in a unified manner.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@gmail.com>
> ---
> libavcodec/cbs.c | 35 +++++++++++++++++++++++++++++++++++
> libavcodec/cbs.h | 15 +++++++++++++++
> 2 files changed, 50 insertions(+)
>
> diff --git a/libavcodec/cbs.c b/libavcodec/cbs.c
> index 47679eca1b..37b080b5ba 100644
> --- a/libavcodec/cbs.c
> +++ b/libavcodec/cbs.c
> @@ -342,6 +342,41 @@ int ff_cbs_write_extradata(CodedBitstreamContext *ctx,
> return 0;
> }
>
> +void ff_cbs_update_video_parameters(CodedBitstreamContext *ctx,
The context argument isn't used at all.
> + AVCodecParameters *par, int profile,
> + int level, int width, int height,
> + int field_order, int color_range,
> + int color_primaries, int color_trc,
> + int color_space, int chroma_location,
> + int video_delay)
> +{
> +#define SET_IF_NONNEGATIVE(elem) \
> + if (elem >= 0) \
> + par->elem = elem;
> + SET_IF_NONNEGATIVE(profile)
> + SET_IF_NONNEGATIVE(level)
> + SET_IF_NONNEGATIVE(width)
> + SET_IF_NONNEGATIVE(height)
> + SET_IF_NONNEGATIVE(field_order)
> + SET_IF_NONNEGATIVE(video_delay)
> +#undef SET_IF_NONNEGATIVE
> +
> +#define SET_IF_VALID(elem, upper_bound) \
> + if (0 <= elem && elem < upper_bound) \
> + par->elem = elem;
> + SET_IF_VALID(color_range, AVCOL_RANGE_NB)
> + SET_IF_VALID(color_trc, AVCOL_TRC_NB)
> + SET_IF_VALID(color_space, AVCOL_SPC_NB)
I think we generally want to admit future values for the 23001-8 / H.273 fields
(see range ..255 on all the metadata filters).
> + SET_IF_VALID(chroma_location, AVCHROMA_LOC_NB)
> +#undef SET_IF_VALID
> +
> + if (0 <= color_primaries && color_primaries <= AVCOL_PRI_SMPTE432
> + || color_primaries == AVCOL_PRI_JEDEC_P22)
> + par->color_primaries = color_primaries;
> +
> + return;
> +}
> +
> int ff_cbs_write_packet(CodedBitstreamContext *ctx,
> AVPacket *pkt,
> CodedBitstreamFragment *frag)
> diff --git a/libavcodec/cbs.h b/libavcodec/cbs.h
> index e1e6055ceb..1655f790cd 100644
> --- a/libavcodec/cbs.h
> +++ b/libavcodec/cbs.h
> @@ -304,6 +304,21 @@ int ff_cbs_write_extradata(CodedBitstreamContext *ctx,
> AVCodecParameters *par,
> CodedBitstreamFragment *frag);
>
> +/**
> + * Update the parameters of an AVCodecParameters structure
> + *
> + * If a parameter is negative, the corresponding member is not
> + * modified. For the color/chroma parameters, only values that
> + * are part of the relevant enumeration are written.
> + */
> +void ff_cbs_update_video_parameters(CodedBitstreamContext *ctx,
> + AVCodecParameters *par, int profile,
> + int level, int width, int height,
> + int field_order, int color_range,
> + int color_primaries, int color_trc,
> + int color_space, int chroma_location,
> + int video_delay);
I find the calls with -1, -1, -1 pretty horrible, and all the extra pointer
arguments being passed around in the metadata filters are not very nice either.
To avoid both of those, how about something like this:
typedef struct foo {
int profile;
int level;
int width;
...
} foo;
init_foo(foo *p)
{
set all fields to minus one (or some other placeholder value)
}
update_codecpar_with_foo(AVCodecPar *par, const foo *p)
{
as above
}
Then in each BSF:
struct BarMetadataContext {
...
foo parameters;
} BarMetadataContext;
update_stuff()
{
...
ctx->parameters.whatever = not-minus-one
}
init()
{
init_foo(&ctx->parameters);
update_stuff()
update_codecpar_with_foo(bsf->par_out, &ctx->foo);
}
What do you think?
Thanks,
- Mark
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