[FFmpeg-cvslog] avcodec/mjpegdec: Try to continue decoding on zero quant matrix value

[Andriy Gelman]

ffmpeg | branch: master | Andriy Gelman <andriy.gelman at gmail.com> | Sat Jul  3 12:25:28 2021 -0400| [78f21f4ec161b9eacb75823740eabd3b87b44efe] | committer: Andriy Gelman

avcodec/mjpegdec: Try to continue decoding on zero quant matrix value

A zero value in the quantization matrix is invalid but in practice will
just set the transform coefficient to zero after inverse quantization.
Try to continue decoding if the AV_EF_EXPLODE flag is not set.

Fixes ticket #9287.

Reviewed-by: Michael Niedermayer <michael at niedermayer.cc>
Signed-off-by: Andriy Gelman <andriy.gelman at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=78f21f4ec161b9eacb75823740eabd3b87b44efe
---

 libavcodec/mjpegdec.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 02a987fd0c..8172dca513 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -217,8 +217,10 @@ int ff_mjpeg_decode_dqt(MJpegDecodeContext *s)
         for (i = 0; i < 64; i++) {
             s->quant_matrixes[index][i] = get_bits(&s->gb, pr ? 16 : 8);
             if (s->quant_matrixes[index][i] == 0) {
-                av_log(s->avctx, AV_LOG_ERROR, "dqt: 0 quant value\n");
-                return AVERROR_INVALIDDATA;
+                int log_level = s->avctx->err_recognition & AV_EF_EXPLODE ? AV_LOG_ERROR : AV_LOG_WARNING;
+                av_log(s->avctx, log_level, "dqt: 0 quant value\n");
+                if (s->avctx->err_recognition & AV_EF_EXPLODE)
+                    return AVERROR_INVALIDDATA;
             }
         }