On Thu, 14 Dec 2023 15:39:11 +0100 Niklas Haas <ffm...@haasn.xyz> wrote:
> From: Niklas Haas <g...@haasn.dev>
>
> Currently, the logic inside the FF_FILTER_FORMATS_QUERY_FUNC branch
> prevents this code from running in the event that we have a filter with
> a single video input and a single audio output, as the resulting audio
> output link will not have its channel counts / samplerates correctly
> initialized to their default values, possibly triggering a segfault
> downstream.
>
> An example of such a filter is vaf_spectrumsynth. Although this
> particular filter already sets up the channel counts and samplerates as
> part of the query function and therefore avoids triggering this bug, the
> bug still exists in principle. (And importantly, sets a wrong precedent)
> ---
> libavfilter/formats.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/libavfilter/formats.c b/libavfilter/formats.c
> index d1c97daf64..114886aeb2 100644
> --- a/libavfilter/formats.c
> +++ b/libavfilter/formats.c
> @@ -808,16 +808,17 @@ int ff_default_query_formats(AVFilterContext *ctx)
> /* Intended fallthrough */
> case FF_FILTER_FORMATS_PASSTHROUGH:
> case FF_FILTER_FORMATS_QUERY_FUNC:
> - type = ctx->nb_inputs ? ctx->inputs [0]->type :
> - ctx->nb_outputs ? ctx->outputs[0]->type :
> AVMEDIA_TYPE_VIDEO;
> - formats = ff_all_formats(type);
> + type = AVMEDIA_TYPE_UNKNOWN;
> + formats = ff_all_formats(ctx->nb_inputs ? ctx->inputs [0]->type :
> + ctx->nb_outputs ? ctx->outputs[0]->type :
> + AVMEDIA_TYPE_VIDEO);
> break;
> }
>
> ret = ff_set_common_formats(ctx, formats);
> if (ret < 0)
> return ret;
> - if (type == AVMEDIA_TYPE_AUDIO) {
> + if (type != AVMEDIA_TYPE_VIDEO) {
> ret = ff_set_common_all_channel_counts(ctx);
> if (ret < 0)
> return ret;
> --
> 2.43.0
>
This patch fixes the underlying issue (alongside the corresponding
adjustment to the conditional from `type == AVMEDIA_TYPE_VIDEO` to `type
!= AVMEDIA_TYPE_AUDIO` in patch 03/15).
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
