[FFmpeg-devel] [PATCH] rtpenc_vp8: Use 15-bit PictureIDs

[Martin Storsjö]

On Tue, 22 Mar 2022, kevin at muxable.com wrote:

> From: Kevin Wang <kevmo314 at gmail.com>
>
> 7-bit PictureIDs are not supported by WebRTC:
> https://groups.google.com/g/discuss-webrtc/c/333-L02vuWA
>
> In practice, 15-bit PictureIDs offer better compatibility.
>
> Signed-off-by: Kevin Wang <kevin at muxable.com>
> ---
> libavformat/rtpenc_vp8.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/libavformat/rtpenc_vp8.c b/libavformat/rtpenc_vp8.c
> index 671d245758..655d44517e 100644
> --- a/libavformat/rtpenc_vp8.c
> +++ b/libavformat/rtpenc_vp8.c
> @@ -35,7 +35,8 @@ void ff_rtp_send_vp8(AVFormatContext *s1, const uint8_t *buf, int size)
>     // partition id 0
>     *s->buf_ptr++ = 0x90;
>     *s->buf_ptr++ = 0x80; // Picture id present
> -    *s->buf_ptr++ = s->frame_count++ & 0x7f;
> +    *s->buf_ptr++ = ((s->frame_count & 0x7f00) >> 8) | 0x80;
> +    *s->buf_ptr++ = s->frame_count++ & 0xff;
>     // Calculate the number of remaining bytes
>     header_size     = s->buf_ptr - s->buf;
>     max_packet_size = s->max_payload_size - header_size;
> -- 
> 2.34.1

LGTM, thanks!

// Martin