[FFmpeg-devel] [PATCH] avfilter/buffersrc: fix overriding unknown channel layouts with negotiated one

[Marton Balint]

On Sat, 23 Mar 2024, Marton Balint wrote:

> Fixes ffplay playback of unknown layouts, when SDL directly supports the audio
> format, such as:
>
> ffplay -f lavfi anullsrc=cl=2C,aformat=s16
>
> Without the patch, "Channel layout change is not supported" errors are
> generated because buffersrc (unknown 2 channel) and buffersink (stereo)
> negotiated a stereo layout, but the stereo layout was never stored in the
> BufferSourceContext.
>
> This fixes a regression of 7251f909721a570726775acf61b2b9c28a950c76, but this
> is more of a regression of the avfilter channel layout conversion
> (1f96db959c1235bb7079d354e09914a0a2608f62).
>
> Signed-off-by: Marton Balint <cus at passwd.hu>
> ---
> libavfilter/buffersrc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libavfilter/buffersrc.c b/libavfilter/buffersrc.c
> index ddcd403785..fcae4f8e69 100644
> --- a/libavfilter/buffersrc.c
> +++ b/libavfilter/buffersrc.c
> @@ -507,7 +507,7 @@ static int config_props(AVFilterLink *link)
>         }
>         break;
>     case AVMEDIA_TYPE_AUDIO:
> -        if (!c->ch_layout.nb_channels) {
> +        if (!c->ch_layout.nb_channels || c->ch_layout.order == AV_CHANNEL_ORDER_UNSPEC) {
>             int ret = av_channel_layout_copy(&c->ch_layout, &link->ch_layout);
>             if (ret < 0)
>                 return ret;

Will apply and backport.

Regards,
Marton