This proved beneficial for performance: For the sample [1] the number
of decicycles in one decode call decreased from
155851561 to
108158037
for Clang 10 and from
168270467 to
128847479 for GCC 9.3. For x86-32
compiled with GCC 9.3 and run on an x64 Haswell the number increased
from
158405517 to
202215769, so that the cached bitstream reader is only
enabled if HAVE_FAST_64BIT is set. These values are the average of 10
runs each looping five times over the input.
[1]: samples.ffmpeg.org/ffmpeg-bugs/trac/ticket2593/fraps_flv1_decoding_errors.avi
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
* Version 2 files support by Konstantin Shishkov
*/
+#include "config.h"
+
+#define CACHED_BITSTREAM_READER HAVE_FAST_64BIT
#define UNCHECKED_BITSTREAM_READER 1
#include "avcodec.h"
#include "get_bits.h"