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[FFmpeg-devel] lavc/svq3: Fix regression decoding some files.

Message ID 20180731002202.144566-1-nbowe@google.com
State Accepted
Commit 5aeb3b008080d8d4a38f245d557dbc9bd6c36dcf
Headers show

Commit Message

Niki Bowe July 31, 2018, 12:22 a.m. UTC 
Fixes some SVQ3 encoded files which fail to decode correctly after 6d6faa2a2d.
These files exhibit lots of artifacts and logs show "Media key encryption is not implemented".
However they decode without artifacts before 6d6faa2a2d.
The attatched patch allows these files to successfully decode, but also reject media key files.

Tested on the files in #6094 and http://samples.mplayerhq.hu/V-codecs/SVQ3/Vertical400kbit.sorenson3.mov
---
 libavcodec/svq3.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

Comments

Carl Eugen Hoyos July 31, 2018, 10:57 p.m. UTC | #1 
2018-07-31 2:22 GMT+02:00, Nikolas Bowe <nbowe-at-google.com@ffmpeg.org>:
> Fixes some SVQ3 encoded files which fail to decode correctly after
> 6d6faa2a2d.

Please provide a sample.

Thank you, Carl Eugen
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Patch

diff --git a/libavcodec/svq3.c b/libavcodec/svq3.c
index fc17081ecf..18a4448ffa 100644
--- a/libavcodec/svq3.c
+++ b/libavcodec/svq3.c
@@ -1064,16 +1064,15 @@  static int svq3_decode_slice_header(AVCodecContext *avctx)
         av_log(s->avctx, AV_LOG_ERROR, "illegal slice type %u \n", slice_id);
         return -1;
     }
-    if (get_bits1(&s->gb_slice)) {
-        avpriv_report_missing_feature(s->avctx, "Media key encryption");
-        return AVERROR_PATCHWELCOME;
-    }
 
     s->slice_type = ff_h264_golomb_to_pict_type[slice_id];
 
     if ((header & 0x9F) == 2) {
-        i = (s->mb_num < 64) ? 5 : av_log2(s->mb_num - 1);
+        i = (s->mb_num < 64) ? 6 : (1 + av_log2(s->mb_num - 1));
         get_bits(&s->gb_slice, i);
+    } else if (get_bits1(&s->gb_slice)) {
+        avpriv_report_missing_feature(s->avctx, "Media key encryption");
+        return AVERROR_PATCHWELCOME;
     }
 
     s->slice_num      = get_bits(&s->gb_slice, 8);