[FFmpeg-devel] [PATCH] lavc/mpeg2dec: fix MPEG2 VA-API interlace decoding issue.

[Jun Zhao]

From: Jun Zhao <jun.zhao at intel.com>

For interlaced frame, it has to call slice_end() for both fields. And
VASliceParameterBufferMPEG2::slice_vertical_position is supposed to be
the position in the picture but not field in this case.

Signed-off-by: Dong, Jerry <jerry.dong at intel.com>
Signed-off-by: Jun Zhao <jun.zhao at intel.com>
---
 libavcodec/mpeg12dec.c   |    9 +++++++++
 libavcodec/vaapi_mpeg2.c |    2 +-
 2 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
index 83e5378..c21f133 100644
--- a/libavcodec/mpeg12dec.c
+++ b/libavcodec/mpeg12dec.c
@@ -2546,6 +2546,15 @@ static int decode_chunks(AVCodecContext *avctx, AVFrame *picture,
                     s2->er.error_count += s2->thread_context[i]->er.error_count;
                 s->slice_count = 0;
             }
+
+            if (s2->first_field) {
+                /* slice ends for the first field */
+                ret = slice_end(avctx, picture);
+                av_assert1(ret == 0);
+                if (ret < 0)
+                    return ret;
+            }
+
             if (last_code == 0 || last_code == SLICE_MIN_START_CODE) {
                 ret = mpeg_decode_postinit(avctx);
                 if (ret < 0) {
diff --git a/libavcodec/vaapi_mpeg2.c b/libavcodec/vaapi_mpeg2.c
index aaed434..b159f49 100644
--- a/libavcodec/vaapi_mpeg2.c
+++ b/libavcodec/vaapi_mpeg2.c
@@ -156,7 +156,7 @@ static int vaapi_mpeg2_decode_slice(AVCodecContext *avctx, const uint8_t *buffer
         .slice_data_flag            = VA_SLICE_DATA_FLAG_ALL,
         .macroblock_offset          = macroblock_offset,
         .slice_horizontal_position  = s->mb_x,
-        .slice_vertical_position    = s->mb_y >> (s->picture_structure != PICT_FRAME),
+        .slice_vertical_position    = s->mb_y,
         .quantiser_scale_code       = quantiser_scale_code,
         .intra_slice_flag           = intra_slice_flag,
     };
-- 
1.7.1