[FFmpeg-devel] [PATCH 1/6] avutil/opt: add AV_OPT_FLAG_CHILD_CONSTS

[Fu, Linjie]

> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> Marton Balint
> Sent: Tuesday, May 12, 2020 03:35
> To: ffmpeg-devel at ffmpeg.org
> Cc: Marton Balint <cus at passwd.hu>
> Subject: [FFmpeg-devel] [PATCH 1/6] avutil/opt: add
> AV_OPT_FLAG_CHILD_CONSTS
> 
> This will be used for AVCodecContext->profile. By specifying constants in the
> encoders we won't have to use the common AVCodecContext options table
> and
> different encoders can use the same profile name even with different values.
> 
> Signed-off-by: Marton Balint <cus at passwd.hu>
> ---
>  doc/APIchanges      | 3 +++
>  libavutil/opt.c     | 3 ++-
>  libavutil/opt.h     | 1 +
>  libavutil/version.h | 2 +-
>  4 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/doc/APIchanges b/doc/APIchanges
> index 75cfdb08b0..235888c174 100644
> --- a/doc/APIchanges
> +++ b/doc/APIchanges
> @@ -15,6 +15,9 @@ libavutil:     2017-10-21
> 
>  API changes, most recent first:
> 
> +2020-05-xx - xxxxxxxxxx - lavu 56.44.101 - opt.h
> +  Add AV_OPT_FLAG_CHILD_CONSTS.
> +
>  2020-05-10 - xxxxxxxxxx - lavu 56.44.100 - hwcontext_vulkan.h
>    Add enabled_inst_extensions, num_enabled_inst_extensions,
> enabled_dev_extensions
>    and num_enabled_dev_extensions fields to AVVulkanDeviceContext
> diff --git a/libavutil/opt.c b/libavutil/opt.c
> index b792dec01c..423313bce2 100644
> --- a/libavutil/opt.c
> +++ b/libavutil/opt.c
> @@ -256,11 +256,12 @@ static int set_string_number(void *obj, void
> *target_obj, const AVOption *o, con
>          }
> 
>          {
> -            const AVOption *o_named = av_opt_find(target_obj, i ? buf : val, o-
> >unit, 0, 0);
>              int res;
>              int ci = 0;
>              double const_values[64];
>              const char * const_names[64];
> +            int search_flags = (o->flags & AV_OPT_FLAG_CHILD_CONSTS) ?
> AV_OPT_SEARCH_CHILDREN : 0;
> +            const AVOption *o_named = av_opt_find(target_obj, i ? buf : val, o-
> >unit, 0, search_flags);
>              if (o_named && o_named->type == AV_OPT_TYPE_CONST)
>                  d = DEFAULT_NUMVAL(o_named);
>              else {
> diff --git a/libavutil/opt.h b/libavutil/opt.h
> index 1969c984dd..e46119572a 100644
> --- a/libavutil/opt.h
> +++ b/libavutil/opt.h
> @@ -291,6 +291,7 @@ typedef struct AVOption {
>  #define AV_OPT_FLAG_RUNTIME_PARAM   (1<<15) ///< a generic
> parameter which can be set by the user at runtime
>  #define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic
> parameter which can be set by the user for filtering
>  #define AV_OPT_FLAG_DEPRECATED      (1<<17) ///< set if option is
> deprecated, users should refer to AVOption.help text for more information
> +#define AV_OPT_FLAG_CHILD_CONSTS    (1<<18) ///< set if option
> constants can also reside in child objects
>  //FIXME think about enc-audio, ... style flags
> 
>      /**
> diff --git a/libavutil/version.h b/libavutil/version.h
> index 48d8a38c42..c4946c1c7e 100644
> --- a/libavutil/version.h
> +++ b/libavutil/version.h
> @@ -80,7 +80,7 @@
> 
>  #define LIBAVUTIL_VERSION_MAJOR  56
>  #define LIBAVUTIL_VERSION_MINOR  44
> -#define LIBAVUTIL_VERSION_MICRO 100
> +#define LIBAVUTIL_VERSION_MICRO 101
> 
>  #define LIBAVUTIL_VERSION_INT
> AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
>                                                 LIBAVUTIL_VERSION_MINOR, \
> --
> 2.16.4

I'm with this idea to specify avctx->profile with candidate options
in child encoder.

Also verified that this would benefit encoders who share the standard
profile options and use avtcx->profile directly. For others we may need
to implement some corresponding changes to transfer from private->profile
to avctx->profile. (But we may keep it for now, and change step by step)

- Linjie