On Tue, Jan 26, 2016 at 6:04 PM, Michael Niedermayer <mich...@niedermayer.cc
> wrote:
> On Tue, Jan 26, 2016 at 05:15:37PM +0100, Matthieu Bouron wrote:
> > From: Matthieu Bouron <matthieu.bou...@stupeflix.com>
> >
> > ---
> >
> > From random 3264x2448 jpegs, scan data copy on a Nexus5 goes from [15,
> 28]ms to [3, 12]ms.
>
> breaks https://trac.ffmpeg.org/raw-attachment/ticket/1527/24bpp.mov
>
Thanks for finding this.
Fixed in the attached patch.
[...]
From d0a2808be8393dc7c2d813d08fc0e4518d0f2bd9 Mon Sep 17 00:00:00 2001
From: Matthieu Bouron <matthieu.bou...@stupeflix.com>
Date: Tue, 26 Jan 2016 17:15:37 +0100
Subject: [PATCH] lavc/mjpegdec: speed up scan data copy
---
libavcodec/mjpegdec.c | 50 ++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 40 insertions(+), 10 deletions(-)
diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 863738d..ada607d 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -1917,24 +1917,54 @@ int ff_mjpeg_find_marker(MJpegDecodeContext *s,
/* unescape buffer of SOS, use special treatment for JPEG-LS */
if (start_code == SOS && !s->ls) {
const uint8_t *src = *buf_ptr;
+ const uint8_t *ptr = src;
uint8_t *dst = s->buffer;
- while (src < buf_end) {
- uint8_t x = *(src++);
+ #define copy_data_segment(skip) do { \
+ ssize_t length = (ptr - src) - (skip); \
+ if (length > 0) { \
+ memcpy(dst, src, length); \
+ dst += length; \
+ src = ptr; \
+ } \
+ } while (0)
+
+ if (s->avctx->codec_id == AV_CODEC_ID_THP) {
+ ptr = buf_end;
+ copy_data_segment(0);
+ } else {
+ while (ptr < buf_end) {
+ uint8_t x = *(ptr++);
- *(dst++) = x;
- if (s->avctx->codec_id != AV_CODEC_ID_THP) {
if (x == 0xff) {
- while (src < buf_end && x == 0xff)
- x = *(src++);
+ ssize_t skip = 0;
+ while (ptr < buf_end && x == 0xff) {
+ x = *(ptr++);
+ skip++;
+ }
- if (x >= 0xd0 && x <= 0xd7)
- *(dst++) = x;
- else if (x)
- break;
+ /* 0xFF, 0xFF, ... */
+ if (skip > 1) {
+ copy_data_segment(skip);
+
+ /* decrement src as it is equal to ptr after the
+ * copy_data_segment macro and we might want to
+ * copy the current value of x later on */
+ src--;
+ }
+
+ if (x < 0xd0 || x > 0xd7) {
+ copy_data_segment(1);
+ if (x)
+ break;
+ }
}
}
+ if (src < ptr)
+ copy_data_segment(0);
}
+ #undef copy_data_segment
+
*unescaped_buf_ptr = s->buffer;
*unescaped_buf_size = dst - s->buffer;
memset(s->buffer + *unescaped_buf_size, 0,
--
2.7.0
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
