[FFmpeg-devel] [PATCH 1/7] avcodec/h263dec: Remove redundant code to set cur_pic_ptr

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Mon Aug 15 14:49:24 EEST 2022


It is done later in ff_mpv_frame_start() (and nobody uses
current_picture_ptr between setting it in ff_mpv_frame_start()).

(The reason the vsynth*-h263-obmc code changes is because
the call to ff_find_unused_picture() now happens after the older
pictures have been unreferenced in ff_mpv_frame_start(),
so that their slots in the picture array can be immediately
reused; the obmc code is somehow buggy and changes its output
depending on the earlier contents of the motion_val buffer.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
---
I'd like to take this opportunity to once again ask anyone familiar
with H.263 to take a look at this OBMC issue.

 libavcodec/h263dec.c                   | 7 -------
 tests/ref/vsynth/vsynth1-h263-obmc     | 4 ++--
 tests/ref/vsynth/vsynth2-h263-obmc     | 4 ++--
 tests/ref/vsynth/vsynth_lena-h263-obmc | 4 ++--
 4 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
index 8db0eccd89..a65f16caea 100644
--- a/libavcodec/h263dec.c
+++ b/libavcodec/h263dec.c
@@ -543,13 +543,6 @@ retry:
             return ret;
     }
 
-    if (!s->current_picture_ptr || s->current_picture_ptr->f->data[0]) {
-        int i = ff_find_unused_picture(s->avctx, s->picture, 0);
-        if (i < 0)
-            return i;
-        s->current_picture_ptr = &s->picture[i];
-    }
-
     avctx->has_b_frames = !s->low_delay;
 
     if (CONFIG_MPEG4_DECODER && avctx->codec_id == AV_CODEC_ID_MPEG4) {
diff --git a/tests/ref/vsynth/vsynth1-h263-obmc b/tests/ref/vsynth/vsynth1-h263-obmc
index b7a267a8cb..a9d0b166cf 100644
--- a/tests/ref/vsynth/vsynth1-h263-obmc
+++ b/tests/ref/vsynth/vsynth1-h263-obmc
@@ -1,4 +1,4 @@
 7dec64380f375e5118b66f3baaaa1e24 *tests/data/fate/vsynth1-h263-obmc.avi
 657320 tests/data/fate/vsynth1-h263-obmc.avi
-844f7ee27fa122e199fe20987b41a15c *tests/data/fate/vsynth1-h263-obmc.out.rawvideo
-stddev:    8.16 PSNR: 29.89 MAXDIFF:  113 bytes:  7603200/  7603200
+f5048b5f0c98833a1d11f8034fb1827f *tests/data/fate/vsynth1-h263-obmc.out.rawvideo
+stddev:    8.12 PSNR: 29.93 MAXDIFF:  113 bytes:  7603200/  7603200
diff --git a/tests/ref/vsynth/vsynth2-h263-obmc b/tests/ref/vsynth/vsynth2-h263-obmc
index 2cef7f551b..2275b6e446 100644
--- a/tests/ref/vsynth/vsynth2-h263-obmc
+++ b/tests/ref/vsynth/vsynth2-h263-obmc
@@ -1,4 +1,4 @@
 2d8a58b295e03f94e6a41468b2d3909e *tests/data/fate/vsynth2-h263-obmc.avi
 208522 tests/data/fate/vsynth2-h263-obmc.avi
-4a939ef99fc759293f2e609bfcacd2a4 *tests/data/fate/vsynth2-h263-obmc.out.rawvideo
-stddev:    6.10 PSNR: 32.41 MAXDIFF:   90 bytes:  7603200/  7603200
+20c4dda7bc5b4da28611a8c731cfa1c5 *tests/data/fate/vsynth2-h263-obmc.out.rawvideo
+stddev:    6.08 PSNR: 32.44 MAXDIFF:   81 bytes:  7603200/  7603200
diff --git a/tests/ref/vsynth/vsynth_lena-h263-obmc b/tests/ref/vsynth/vsynth_lena-h263-obmc
index 5b963107f6..a18ef8e9e3 100644
--- a/tests/ref/vsynth/vsynth_lena-h263-obmc
+++ b/tests/ref/vsynth/vsynth_lena-h263-obmc
@@ -1,4 +1,4 @@
 3c6946f808412ac320be9e0c36051ea2 *tests/data/fate/vsynth_lena-h263-obmc.avi
 154730 tests/data/fate/vsynth_lena-h263-obmc.avi
-588d992d9d8096da8bdc5027268da914 *tests/data/fate/vsynth_lena-h263-obmc.out.rawvideo
-stddev:    5.39 PSNR: 33.49 MAXDIFF:   82 bytes:  7603200/  7603200
+acc9705f4c9a019c2032a875a6a715ae *tests/data/fate/vsynth_lena-h263-obmc.out.rawvideo
+stddev:    5.39 PSNR: 33.50 MAXDIFF:   77 bytes:  7603200/  7603200
-- 
2.34.1



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