[FFmpeg-devel] [PATCH 2/3] avformat/matroskaenc: Remove pointless casts

[James Almer]

On 5/21/2020 10:24 PM, Andreas Rheinhardt wrote:
> by using a const void * pointer as an intermediate.
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---
> Why is the side-data API (both the packet as well as the stream one)
> actually based around uint8_t * and not pointers to void despite
> side-data being mostly structures and not just buffers?

uint8_t* is ubiquitous in the codebase for pointers to allocated data.
And if you look at the early side data types (palette, new extradata),
it's not surprising they were defined this way (Assuming these functions
are as old as the very first side data types).

> 
>  libavformat/matroskaenc.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
> index f5968c17b4..9ad590cb93 100644
> --- a/libavformat/matroskaenc.c
> +++ b/libavformat/matroskaenc.c
> @@ -836,7 +836,7 @@ static void mkv_write_video_color(AVIOContext *pb, const AVStream *st,
>      uint8_t colour[(2 + 1 + 8) * 18 + (2 + 1) + 1];
>      AVIOContext buf, *dyn_cp = &buf;
>      int colorinfo_size;
> -    const uint8_t *side_data;
> +    const void *side_data;
>  
>      ffio_init_context(dyn_cp, colour, sizeof(colour), 1, NULL, NULL, NULL, NULL);
>  
> @@ -869,8 +869,7 @@ static void mkv_write_video_color(AVIOContext *pb, const AVStream *st,
>      side_data = av_stream_get_side_data(st, AV_PKT_DATA_CONTENT_LIGHT_LEVEL,
>                                          NULL);
>      if (side_data) {
> -        const AVContentLightMetadata *metadata =
> -            (const AVContentLightMetadata*)side_data;
> +        const AVContentLightMetadata *metadata = side_data;
>          put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOCOLORMAXCLL,  metadata->MaxCLL);
>          put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOCOLORMAXFALL, metadata->MaxFALL);
>      }
> @@ -880,8 +879,7 @@ static void mkv_write_video_color(AVIOContext *pb, const AVStream *st,
>      if (side_data) {
>          ebml_master meta_element = start_ebml_master(
>              dyn_cp, MATROSKA_ID_VIDEOCOLORMASTERINGMETA, 10 * (2 + 1 + 8));
> -        const AVMasteringDisplayMetadata *metadata =
> -            (const AVMasteringDisplayMetadata*)side_data;
> +        const AVMasteringDisplayMetadata *metadata = side_data;
>          if (metadata->has_primaries) {
>              put_ebml_float(dyn_cp, MATROSKA_ID_VIDEOCOLOR_RX,
>                             av_q2d(metadata->display_primaries[0][0]));
>