[FFmpeg-devel] [PATCH v2 1/2] lavc: consider an error during decoder draining as EOF

[wm4]

On Thu,  2 Mar 2017 10:45:23 +0100
wm4 <nfxjfg at googlemail.com> wrote:

> There is no reason that draining couldn't return an error or two. But
> some decoders don't handle this very well, and might always return an
> error. This can lead to API users getting into an infinite loop and
> burning CPU, because no progress is made and EOF is never returned.
> 
> In fact, ffmpeg.c contains a hack against such a case. It is removed
> with this patch. This particular error case seems to have been fixed
> since the hack was added, though.
> 
> This might lose frames if decoding returns errors during draining.
> ---
> Minor lavc bump missing.
> ---
>  libavcodec/utils.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
> index 1156e43079..db3adb18d4 100644
> --- a/libavcodec/utils.c
> +++ b/libavcodec/utils.c
> @@ -2807,12 +2807,12 @@ static int do_decode(AVCodecContext *avctx, AVPacket *pkt)
>      if (ret == AVERROR(EAGAIN))
>          ret = pkt->size;
>  
> -    if (ret < 0)
> -        return ret;
> -
>      if (avctx->internal->draining && !got_frame)
>          avctx->internal->draining_done = 1;
>  
> +    if (ret < 0)
> +        return ret;
> +
>      if (ret >= pkt->size) {
>          av_packet_unref(avctx->internal->buffer_pkt);
>      } else {

Both patches pushed, with some changes to the commit message of the
first one. Also I just noticed that I forgot the minor lavc bump, but I
guess it's not too important anyway.