[FFmpeg-cvslog] avcodec/cbs_mpeg2: use memcpy when assembling fragments

[James Almer]

ffmpeg | branch: master | James Almer <jamrial at gmail.com> | Mon Apr 23 23:39:54 2018 -0300| [0161d91db01ae0b5d516232d92764f5a898cedc6] | committer: James Almer

avcodec/cbs_mpeg2: use memcpy when assembling fragments

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>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0161d91db01ae0b5d516232d92764f5a898cedc6
---

 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 bfb64a0851..94b9591b21 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);