From: "Ronald S. Bultje" <rsbul...@gmail.com>
Commit message by James Darnley
The shortcut is based on end-of-block positions. This leads to some
coefficients not being unquantized. This is the symptom of the bug.
A possible candidate for the real bug is the scan table used here in
unquantize does not appear to match the one used in wmv1. That might be
because h263_unquantize_intra uses the inter scan table.
We can avoid the bug by not using the shortcut.
---
libavcodec/mpegvideo.c | 2 +-
libavcodec/x86/mpegvideo.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c
index e5424cbacf..568e782dd6 100644
--- a/libavcodec/mpegvideo.c
+++ b/libavcodec/mpegvideo.c
@@ -222,7 +222,7 @@ static void dct_unquantize_h263_intra_c(MpegEncContext *s,
}else{
qadd = 0;
}
- if(s->ac_pred)
+ if(s->ac_pred || s->avctx->codec_id == AV_CODEC_ID_WMV1)
nCoeffs=63;
else
nCoeffs= s->inter_scantable.raster_end[ s->block_last_index[n] ];
diff --git a/libavcodec/x86/mpegvideo.c b/libavcodec/x86/mpegvideo.c
index 35a8264804..43df9a71b5 100644
--- a/libavcodec/x86/mpegvideo.c
+++ b/libavcodec/x86/mpegvideo.c
@@ -48,7 +48,7 @@ static void dct_unquantize_h263_intra_mmx(MpegEncContext *s,
qadd = 0;
level= block[0];
}
- if(s->ac_pred)
+ if(s->ac_pred || s->avctx->codec_id == AV_CODEC_ID_WMV1)
nCoeffs=63;
else
nCoeffs= s->inter_scantable.raster_end[ s->block_last_index[n] ];
--
2.13.1
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