[FFmpeg-cvslog] mjpegb: don't return 0 at the end of frame decoding.

[Ronald S. Bultje]

ffmpeg | branch: release/0.8 | Ronald S. Bultje <rsbultje at gmail.com> | Fri Feb 17 16:27:36 2012 -0800| [33149928edef047fb6391cf8a84602a213c62921] | committer: Reinhard Tartler

mjpegb: don't return 0 at the end of frame decoding.

Return 0 indicates "please return the same data again", i.e. it causes
an infinite loop. Instead, return that we consumed the buffer if we
finished decoding succesfully, or return an error if an error occurred.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org
(cherry picked from commit 74699ac8c8b562e9f8d26e21482b89585365774a)

Signed-off-by: Anton Khirnov <anton at khirnov.net>
Signed-off-by: Reinhard Tartler <siretart at tauware.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=33149928edef047fb6391cf8a84602a213c62921
---

 libavcodec/mjpegbdec.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/mjpegbdec.c b/libavcodec/mjpegbdec.c
index 837304e..454ba6f 100644
--- a/libavcodec/mjpegbdec.c
+++ b/libavcodec/mjpegbdec.c
@@ -66,7 +66,7 @@ read_header:
     if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g'))
     {
         av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n");
-        return 0;
+        return AVERROR_INVALIDDATA;
     }
 
     field_size = get_bits_long(&hgb, 32); /* field size */
@@ -142,7 +142,7 @@ read_header:
         picture->quality*= FF_QP2LAMBDA;
     }
 
-    return buf_ptr - buf;
+    return buf_size;
 }
 
 AVCodec ff_mjpegb_decoder = {