[FFmpeg-devel] [PATCH] Updated video filtering example

[Stefano Sabatini]

On date Tuesday 2012-06-26 09:18:33 +0100, Gavin Kinsey encoded:
> Updated the video filtering example program based on the audio one.

[...]
> From b6bbe1a6eca3e822fca45b8678dde951c76cd293 Mon Sep 17 00:00:00 2001
> From: Gavin Kinsey <gkinsey at ad-holdings.co.uk>
> Date: Tue, 26 Jun 2012 09:16:16 +0100
> Subject: [PATCH] Updated video filtering example
> 
> ---
>  doc/examples/filtering_video.c |   36 ++++++++++++++++++++++++++----------
>  1 files changed, 26 insertions(+), 10 deletions(-)
> 
> diff --git a/doc/examples/filtering_video.c b/doc/examples/filtering_video.c
> index 29fb77b..dd9f798 100644
> --- a/doc/examples/filtering_video.c
> +++ b/doc/examples/filtering_video.c
> @@ -34,6 +34,7 @@
>  #include <libavfilter/avfiltergraph.h>
>  #include <libavfilter/avcodec.h>
>  #include <libavfilter/buffersink.h>
> +#include <libavfilter/buffersrc.h>
>  
>  const char *filter_descr = "scale=78:24";
>  
> @@ -87,13 +88,17 @@ static int init_filters(const char *filters_descr)
>      AVFilterInOut *outputs = avfilter_inout_alloc();
>      AVFilterInOut *inputs  = avfilter_inout_alloc();
>      enum PixelFormat pix_fmts[] = { PIX_FMT_GRAY8, PIX_FMT_NONE };
> +    AVBufferSinkParams *buffersink_params;
> +
>      filter_graph = avfilter_graph_alloc();
>  
>      /* buffer video source: the decoded frames from the decoder will be inserted here. */
> -    snprintf(args, sizeof(args), "%d:%d:%d:%d:%d:%d:%d",
> -             dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt,
> -             dec_ctx->time_base.num, dec_ctx->time_base.den,
> -             dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den);
> +    snprintf(args, sizeof(args),
> +            "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
> +            dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt,
> +            dec_ctx->time_base.num, dec_ctx->time_base.den,
> +            dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den);
> +
>      ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in",
>                                         args, NULL, filter_graph);
>      if (ret < 0) {
> @@ -102,8 +107,11 @@ static int init_filters(const char *filters_descr)
>      }
>  
>      /* buffer video sink: to terminate the filter chain. */
> +    buffersink_params = av_buffersink_params_alloc();
> +    buffersink_params->pixel_fmts = pix_fmts;
>      ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out",
> -                                       NULL, pix_fmts, filter_graph);
> +                                       NULL, buffersink_params, filter_graph);
> +    av_free(buffersink_params);
>      if (ret < 0) {
>          av_log(NULL, AV_LOG_ERROR, "Cannot create buffer sink\n");
>          return ret;
> @@ -191,7 +199,6 @@ int main(int argc, char **argv)
>              avcodec_get_frame_defaults(&frame);
>              got_frame = 0;
>              ret = avcodec_decode_video2(dec_ctx, &frame, &got_frame, &packet);
> -            av_free_packet(&packet);

Any reason for which you moved this to the end of the loop?

>              if (ret < 0) {
>                  av_log(NULL, AV_LOG_ERROR, "Error decoding video\n");
>                  break;
> @@ -201,18 +208,27 @@ int main(int argc, char **argv)
>                  frame.pts = av_frame_get_best_effort_timestamp(&frame);
>  
>                  /* push the decoded frame into the filtergraph */
> -                av_vsrc_buffer_add_frame(buffersrc_ctx, &frame, 0);
> +                if (av_buffersrc_add_frame(buffersrc_ctx, &frame, 0) < 0) {
> +                    av_log(NULL, AV_LOG_ERROR, "Error while feeding the filtergraph\n");
> +                    break;
> +                }
>  
>                  /* pull filtered pictures from the filtergraph */
> -                while (avfilter_poll_frame(buffersink_ctx->inputs[0])) {
> -                    av_buffersink_get_buffer_ref(buffersink_ctx, &picref, 0);
> +                while (1) {
> +                    ret = av_buffersink_get_buffer_ref(buffersink_ctx, &picref, 0);
> +                    if(ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
> +                        break;
> +                    if(ret < 0)
> +                        goto end;
> +
>                      if (picref) {
>                          display_picref(picref, buffersink_ctx->inputs[0]->time_base);
> -                        avfilter_unref_buffer(picref);
> +                        avfilter_unref_bufferp(&picref);
>                      }
>                  }
>              }
>          }
> +        av_free_packet(&packet);

And patch looks good, thanks.
-- 
FFmpeg = Fundamentalist and Fancy Mind-dumbing Powered Exxagerate Geek