[libav-devel] [PATCH 06/14] avcodec/cbs_mpeg2: use memcpy when assembling fragments

Luca Barbato lu_zero at gentoo.org
Sat May 4 14:14:19 CEST 2019


From: James Almer <jamrial at gmail.com>

before:
419022 decicycles in assemble_fragment,    2047 runs,      1 skips

after:
104621 decicycles in assemble_fragment,    2045 runs,      3 skips

Benched with a 2 minutes long 720x480 DVD mpeg2 sample.

Reviewed-by: Michael Niedermayer <michael at niedermayer.cc>
Signed-off-by: James Almer <jamrial at gmail.com>
---
 libavcodec/cbs_mpeg2.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavcodec/cbs_mpeg2.c b/libavcodec/cbs_mpeg2.c
index 7fa13c64fa..7f484267fa 100644
--- a/libavcodec/cbs_mpeg2.c
+++ b/libavcodec/cbs_mpeg2.c
@@ -362,7 +362,7 @@ static int cbs_mpeg2_assemble_fragment(CodedBitstreamContext *ctx,
                                        CodedBitstreamFragment *frag)
 {
     uint8_t *data;
-    size_t size, dp, sp;
+    size_t size, dp;
     int i;
 
     size = 0;
@@ -382,8 +382,8 @@ static int cbs_mpeg2_assemble_fragment(CodedBitstreamContext *ctx,
         data[dp++] = 0;
         data[dp++] = 1;
 
-        for (sp = 0; sp < unit->data_size; sp++)
-            data[dp++] = unit->data[sp];
+        memcpy(data + dp, unit->data, unit->data_size);
+        dp += unit->data_size;
     }
 
     av_assert0(dp == size);
-- 
2.12.2



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