[FFmpeg-devel] [PATCH 1/7] lavfi: add a closed field to AVFilerLink.

[Stefano Sabatini]

On date Monday 2012-08-20 23:28:09 +0200, Nicolas George encoded:
> It will help forward errors and maintain consistency.
> 
> Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
> ---
>  libavfilter/audio.c    |    5 +++++
>  libavfilter/avfilter.c |    9 +++++++++
>  libavfilter/avfilter.h |   17 +++++++++++++++++
>  libavfilter/version.h  |    2 +-
>  libavfilter/video.c    |    5 +++++
>  5 files changed, 37 insertions(+), 1 deletion(-)
> 
> diff --git a/libavfilter/audio.c b/libavfilter/audio.c
> index 525b471..e7306b1 100644
> --- a/libavfilter/audio.c
> +++ b/libavfilter/audio.c
> @@ -172,6 +172,11 @@ int ff_filter_samples_framed(AVFilterLink *link, AVFilterBufferRef *samplesref)
>  
>      FF_TPRINTF_START(NULL, filter_samples); ff_tlog_link(NULL, link, 1);
>  
> +    if (link->closed) {
> +        avfilter_unref_buffer(samplesref);
> +        return AVERROR_EOF;
> +    }
> +
>      if (!(filter_samples = dst->filter_samples))
>          filter_samples = default_filter_samples;
>  
> diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c
> index b1df537..861a57d 100644
> --- a/libavfilter/avfilter.c
> +++ b/libavfilter/avfilter.c
> @@ -159,6 +159,11 @@ void avfilter_link_free(AVFilterLink **link)
>      av_freep(link);
>  }
>  
> +void avfilter_link_set_closed(AVFilterLink *link, int closed)
> +{
> +    link->closed = closed;
> +}
> +
>  int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
>                             unsigned filt_srcpad_idx, unsigned filt_dstpad_idx)
>  {
> @@ -325,6 +330,8 @@ int ff_request_frame(AVFilterLink *link)
>      int ret = -1;
>      FF_TPRINTF_START(NULL, request_frame); ff_tlog_link(NULL, link, 1);
>  
> +    if (link->closed)
> +        return AVERROR_EOF;
>      if (link->srcpad->request_frame)
>          ret = link->srcpad->request_frame(link);
>      else if (link->src->inputs[0])
> @@ -335,6 +342,8 @@ int ff_request_frame(AVFilterLink *link)
>          ff_filter_samples_framed(link, pbuf);
>          return 0;
>      }
> +    if (ret == AVERROR_EOF)
> +        link->closed = 1;
>      return ret;
>  }
>  
> diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
> index 9891a72..c0575ce 100644
> --- a/libavfilter/avfilter.h
> +++ b/libavfilter/avfilter.h
> @@ -697,6 +697,18 @@ struct AVFilterLink {
>       * by the filters.
>       */
>      AVFilterBufferRef *cur_buf_copy;
> +
> +    /**

> +     * True if the link is closed.

Nit: Set to a positive value if the link is closed ("true" is ambiguous).


> +     * If set, all attemps of start_frame, filter_samples or request_frame
> +     * will fail with AVERROR_EOF, and if necessary the reference will be
> +     * destroyed.
> +     * If request_frame returns AVERROR_EOF, this flag is set on the
> +     * corresponding link.
> +     * It can be set also be set by either the source or the destination
> +     * filter.
> +     */
> +    int closed;
>  };
>  
>  /**
> @@ -717,6 +729,11 @@ int avfilter_link(AVFilterContext *src, unsigned srcpad,
>  void avfilter_link_free(AVFilterLink **link);
>  

>  /**
> + * Set the closed field of a link.
> + */
> +void avfilter_link_set_closed(AVFilterLink *link, int closed);

So I suppose this can be used also for *opening* a link?

> +
> +/**
>   * Negotiate the media format, dimensions, etc of all inputs to a filter.
>   *
>   * @param filter the filter to negotiate the properties for its inputs
> diff --git a/libavfilter/version.h b/libavfilter/version.h
> index db415d9..a008d94 100644
> --- a/libavfilter/version.h
> +++ b/libavfilter/version.h
> @@ -29,7 +29,7 @@
>  #include "libavutil/avutil.h"
>  
>  #define LIBAVFILTER_VERSION_MAJOR  3
> -#define LIBAVFILTER_VERSION_MINOR  12
> +#define LIBAVFILTER_VERSION_MINOR  13
>  #define LIBAVFILTER_VERSION_MICRO 100
>  
>  #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
> diff --git a/libavfilter/video.c b/libavfilter/video.c
> index 86332bc..9ab8edb 100644
> --- a/libavfilter/video.c
> +++ b/libavfilter/video.c
> @@ -248,6 +248,11 @@ int ff_start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
>  
>      FF_TPRINTF_START(NULL, start_frame); ff_tlog_link(NULL, link, 0); ff_tlog(NULL, " "); ff_tlog_ref(NULL, picref, 1);
>  
> +    if (link->closed) {
> +        avfilter_unref_buffer(picref);
> +        return AVERROR_EOF;
> +    }
> +
>      if (!(start_frame = dst->start_frame))
>          start_frame = default_start_frame;

Looks good to me, but I'm not sure which specific problem it is
addressing.
-- 
FFmpeg = Frenzy & Fierce Monstrous Proud Excellent Game