diff mbox

[FFmpeg-devel,2/2,v3] avcodec/vc1: fix decoding of old WMV3 format

Message ID a636a6a8-b468-04c4-0175-24a1e3a370dc@carpalis.nl
State Accepted
Commit b6402278322d1f64810cac4bea26d34d7b9a2e6a
Headers show

Commit Message

Jerome Borsboom Jan. 12, 2019, 3:14 p.m. UTC
The position of the second MV predicitor candidate is slightly different
for the old WMV3 format indicated by RES_RTM_FLAG. This patch fixes
decoding of niceday.wmv on the samples server.

Fixes: #6641

Signed-off-by: Jerome Borsboom <jerome.borsboom@carpalis.nl>
---
This revision removes a spurious whitespace that was left behind.

 libavcodec/vc1.c      | 5 -----
 libavcodec/vc1_pred.c | 5 ++++-
 2 files changed, 4 insertions(+), 6 deletions(-)

Comments

Carl Eugen Hoyos Jan. 12, 2019, 3:48 p.m. UTC | #1
2019-01-12 16:14 GMT+01:00, Jerome Borsboom <jerome.borsboom@carpalis.nl>:
> The position of the second MV predicitor candidate is slightly different
> for the old WMV3 format indicated by RES_RTM_FLAG. This patch fixes
> decoding of niceday.wmv on the samples server.
>
> Fixes: #6641
>
> Signed-off-by: Jerome Borsboom <jerome.borsboom@carpalis.nl>
> ---
> This revision removes a spurious whitespace that was left behind.

Patch applied.

Thank you, Carl Eugen
diff mbox

Patch

diff --git a/libavcodec/vc1.c b/libavcodec/vc1.c
index 3581d87b57..e102b931d8 100644
--- a/libavcodec/vc1.c
+++ b/libavcodec/vc1.c
@@ -379,11 +379,6 @@  int ff_vc1_decode_sequence_header(AVCodecContext *avctx, VC1Context *v, GetBitCo
     } else {
         v->res_rtm_flag = get_bits1(gb); //reserved
     }
-    if (!v->res_rtm_flag) {
-        av_log(avctx, AV_LOG_ERROR,
-               "Old WMV3 version detected, some frames may be decoded incorrectly\n");
-        //return -1;
-    }
     //TODO: figure out what they mean (always 0x402F)
     if (!v->res_fasttx)
         skip_bits(gb, 16);
diff --git a/libavcodec/vc1_pred.c b/libavcodec/vc1_pred.c
index 0b22d9916c..e1758a3817 100644
--- a/libavcodec/vc1_pred.c
+++ b/libavcodec/vc1_pred.c
@@ -275,7 +275,10 @@  void ff_vc1_pred_mv(VC1Context *v, int n, int dmv_x, int dmv_y,
         //in 4-MV mode different blocks have different B predictor position
         switch (n) {
         case 0:
-            off = (s->mb_x > 0) ? -1 : 1;
+            if (v->res_rtm_flag)
+                off = s->mb_x ? -1 : 1;
+            else
+                off = s->mb_x ? -1 : 2 * s->mb_width - wrap - 1;
             break;
         case 1:
             off = (s->mb_x == (s->mb_width - 1)) ? -1 : 1;