[FFmpeg-devel] [PATCH]ffmpeg: Check the return values of two functions

[Nicolas George]

Le quartidi 24 pluviôse, an CCXXV, Carl Eugen Hoyos a écrit :
> Hi!
> 
> Attached patch written yesterday silences warnings when compiling 
> ffmpeg.c, don't know how useful it is, only fate-tested.
> 
> Please comment, Carl Eugen

> From 525aff909aec50d4e1a49f289ff9069300a4b51f Mon Sep 17 00:00:00 2001
> From: Carl Eugen Hoyos <cehoyos at ag.or.at>
> Date: Sun, 12 Feb 2017 16:41:21 +0100
> Subject: [PATCH] ffmpeg: Check the return value of two functions declared
>  "warn_unused_result".
> 
> ---
>  ffmpeg.c |   20 ++++++++++++++------
>  1 file changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/ffmpeg.c b/ffmpeg.c
> index 06570c0..9952da6 100644
> --- a/ffmpeg.c
> +++ b/ffmpeg.c
> @@ -215,14 +215,18 @@ static void sub2video_copy_rect(uint8_t *dst, int dst_linesize, int w, int h,
>  static void sub2video_push_ref(InputStream *ist, int64_t pts)
>  {
>      AVFrame *frame = ist->sub2video.frame;
> -    int i;
> +    int i, ret;
>  
>      av_assert1(frame->data[0]);
>      ist->sub2video.last_pts = frame->pts = pts;
> -    for (i = 0; i < ist->nb_filters; i++)
> -        av_buffersrc_add_frame_flags(ist->filters[i]->filter, frame,
> +    for (i = 0; i < ist->nb_filters; i++) {

> +        ret = av_buffersrc_add_frame_flags(ist->filters[i]->filter, frame,
>                                       AV_BUFFERSRC_FLAG_KEEP_REF |
>                                       AV_BUFFERSRC_FLAG_PUSH);

When the changes are that small, I think it is better to fix the
indentation at the same time rather than leave it like that or fix it in
a separate commit.

> +        if (ret < 0)
> +            av_log(ist->filters[i]->filter, AV_LOG_ERROR,

> +                   "Failed to add a frame to the buffer source.\n");

Please mention it is a "subtitle video frame" and include the error
message itself (av_err2str(ret)).

> +    }
>  }
>  
>  static void sub2video_update(InputStream *ist, AVSubtitle *sub)
> @@ -290,12 +294,16 @@ static void sub2video_heartbeat(InputStream *ist, int64_t pts)
>  
>  static void sub2video_flush(InputStream *ist)
>  {
> -    int i;
> +    int i, ret;
>  
>      if (ist->sub2video.end_pts < INT64_MAX)
>          sub2video_update(ist, NULL);
> -    for (i = 0; i < ist->nb_filters; i++)
> -        av_buffersrc_add_frame(ist->filters[i]->filter, NULL);
> +    for (i = 0; i < ist->nb_filters; i++) {
> +        ret = av_buffersrc_add_frame(ist->filters[i]->filter, NULL);
> +        if (ret < 0)
> +            av_log(ist->filters[i]->filter, AV_LOG_ERROR,
> +                   "Failed to add a frame to the buffer source.\n");

Same as above of course.

> +    }
>  }
>  
>  /* end of sub2video hack */

Apart from that, the patch looks good to me in principle.

Regards,

-- 
  Nicolas George
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