[FFmpeg-devel] [PATCH 1/7] avcodec/ffv1dec: add missing error messages when a frame is invalid

[Michael Niedermayer]

On Wed, Mar 07, 2018 at 04:45:20PM +0100, Jerome Martinez wrote:
> A buggy file (before the patch preventing such issue is applied):
> ffmpeg -y -f lavfi -i mandelbrot=s=31x31 -vframes 1 -c ffv1 -slices 961
> a.mkv
> 
> Then with:
> ffmpeg -y -f lavfi -i mandelbrot=s=31x31 -vframes 1 source.jpg
> ffmpeg -y -i a.mkv a.jpg
> 
> There is no error message despite the fact the stream was not correctly
> decoded (a.jpg is not like source.jpg), but user is not informed that the
> decoding was not good.
> 
> This patch adds error message to the output when relevant.
> 
> 

>  ffv1dec.c |   13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 3c17506214ec584128ad4e194acee98737f987da  0001-avcodec-ffv1dec-add-missing-error-messages-when-a-fr.patch
> From 04f7275bdefe56ca2ff5d175de6e392f60c31bc3 Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Martinez?= <jerome at mediaarea.net>
> Date: Wed, 7 Mar 2018 10:36:36 +0100
> Subject: [PATCH 1/7] avcodec/ffv1dec: add missing error messages when a frame
>  is invalid
> 
> ---
>  libavcodec/ffv1dec.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/ffv1dec.c b/libavcodec/ffv1dec.c
> index 3d2ee2569f..94bd60ad2b 100644
> --- a/libavcodec/ffv1dec.c
> +++ b/libavcodec/ffv1dec.c
> @@ -296,6 +296,7 @@ static int decode_slice(AVCodecContext *c, void *arg)
>          if (decode_slice_header(f, fs) < 0) {
>              fs->slice_x = fs->slice_y = fs->slice_height = fs->slice_width = 0;
>              fs->slice_damaged = 1;
> +            av_log(f->avctx, AV_LOG_ERROR, "Invalid content found while parsing slice header\n");
>              return AVERROR_INVALIDDATA;
>          }
>      }

> @@ -432,8 +433,10 @@ static int read_extra_header(FFV1Context *f)
>      if (f->version > 2) {
>          c->bytestream_end -= 4;
>          f->micro_version = get_symbol(c, state, 0);
> -        if (f->micro_version < 0)
> +        if (f->micro_version < 0) {
> +            av_log(f->avctx, AV_LOG_ERROR, "Invalid micro_version in global header\n");

In the cases where the error is about a scalar value, that value should
be printed in the error message (unless it was alread printed elsewhere)

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

He who knows, does not speak. He who speaks, does not know. -- Lao Tsu
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