[FFmpeg-devel] [PATCH] vf_overlay: add logic for avoiding overlaying frames with PTS > main frame PTS

[Paul B Mahol]

On 1/10/12, Stefano Sabatini <stefasab at gmail.com> wrote:
> Also add debug logging messages for helping tracking down similar
> issues.
>
> Fix trac ticket #467.
> ---
>  libavfilter/vf_overlay.c |   41 +++++++++++++++++++++++++++++------------
>  1 files changed, 29 insertions(+), 12 deletions(-)
>
> diff --git a/libavfilter/vf_overlay.c b/libavfilter/vf_overlay.c
> index 062783e..9600061 100644
> --- a/libavfilter/vf_overlay.c
> +++ b/libavfilter/vf_overlay.c
> @@ -25,6 +25,8 @@
>   * overlay one video on top of another
>   */
>
> +/* #define DEBUG */

Is this really needed?
> +
>  #include "avfilter.h"
>  #include "libavutil/eval.h"
>  #include "libavutil/avstring.h"
> @@ -75,7 +77,7 @@ typedef struct {
>      uint8_t overlay_rgba_map[4];
>      uint8_t overlay_has_alpha;
>
> -    AVFilterBufferRef *overpicref;
> +    AVFilterBufferRef *overpicref, *overpicref_next;
>
>      int main_pix_step[4];       ///< steps per pixel for each plane of the
> main output
>      int overlay_pix_step[4];    ///< steps per pixel for each plane of the
> overlay
> @@ -144,6 +146,8 @@ static av_cold void uninit(AVFilterContext *ctx)
>
>      if (over->overpicref)
>          avfilter_unref_buffer(over->overpicref);
> +    if (over->overpicref_next)
> +        avfilter_unref_buffer(over->overpicref_next);
>  }
>
>  static int query_formats(AVFilterContext *ctx)
> @@ -302,22 +306,33 @@ static void start_frame(AVFilterLink *inlink,
> AVFilterBufferRef *inpicref)
>      AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
>      AVFilterContext *ctx = inlink->dst;
>      OverlayContext *over = ctx->priv;
> +    av_unused AVFilterLink *outlink = ctx->outputs[0];
>
>      inlink->dst->outputs[0]->out_buf = outpicref;
>      outpicref->pts = av_rescale_q(outpicref->pts,
> ctx->inputs[MAIN]->time_base,
>                                    ctx->outputs[0]->time_base);
>
>      if (!over->overpicref || over->overpicref->pts < outpicref->pts) {
> -        AVFilterBufferRef *old = over->overpicref;
> -        over->overpicref = NULL;
> -        avfilter_request_frame(ctx->inputs[OVERLAY]);
> -        if (over->overpicref) {
> -            if (old)
> -                avfilter_unref_buffer(old);
> -        } else
> -            over->overpicref = old;
> +        if (!over->overpicref_next)
> +            avfilter_request_frame(ctx->inputs[OVERLAY]);
> +
> +        if (over->overpicref && over->overpicref_next &&
> +            over->overpicref_next->pts <= outpicref->pts) {
> +            avfilter_unref_buffer(over->overpicref);
> +            over->overpicref = over->overpicref_next;
> +            over->overpicref_next = NULL;
> +        }
>      }
>
> +#ifdef DEBUG

Use av_dlog() instead.
> +    av_log(ctx, AV_LOG_DEBUG, "main_pts:%"PRId64" main_pts_time:%f",
> +           outpicref->pts, outpicref ->pts * av_q2d(outlink->time_base));
> +    if (over->overpicref)
> +        av_log(ctx, AV_LOG_DEBUG, " over_pts:%"PRId64" over_pts_time:%f",
> +               over->overpicref->pts, over->overpicref->pts *
> av_q2d(outlink->time_base));
> +    av_dlog(ctx, "\n");
> +#endif
> +
>      avfilter_start_frame(inlink->dst->outputs[0], outpicref);
>  }
>
> @@ -326,9 +341,11 @@ static void start_frame_overlay(AVFilterLink *inlink,
> AVFilterBufferRef *inpicre
>      AVFilterContext *ctx = inlink->dst;
>      OverlayContext *over = ctx->priv;
>
> -    over->overpicref = inpicref;
> -    over->overpicref->pts = av_rescale_q(inpicref->pts,
> ctx->inputs[OVERLAY]->time_base,
> -                                         ctx->outputs[0]->time_base);
> +    inpicref->pts = av_rescale_q(inpicref->pts,
> ctx->inputs[OVERLAY]->time_base,
> +                                 ctx->outputs[0]->time_base);
> +
> +    if (!over->overpicref) over->overpicref      = inpicref;
> +    else                   over->overpicref_next = inpicref;
>  }
>
>  // divide by 255 and round to nearest
> --
> 1.7.5.4
>
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