From ee3e36315e25d74da1079b4bafe3fd36fc9f3406 Mon Sep 17 00:00:00 2001
From: Gwenole Beauchesne <gbeauchesne@splitted-desktop.com>
Date: Tue, 24 Feb 2009 16:12:47 +0000
Subject: [PATCH] Add ff_h263_find_resync_marker() to find the bit position of
the next resync_marker, if any. patch by Gwenole Beauchesne gbeauchesne
splitted-desktopcom based on suggested implementation by me
Originally committed as revision 17560 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
libavcodec/h263.c | 21 +++++++++++++++++++++
libavcodec/mpegvideo.h | 1 +
2 files changed, 22 insertions(+)
diff --git a/libavcodec/h263.c b/libavcodec/h263.c
index b02b0ad2f4c..2a25cdae671 100644
--- a/libavcodec/h263.c
+++ b/libavcodec/h263.c
@@ -3292,6 +3292,27 @@ void ff_mpeg4_clean_buffers(MpegEncContext *s)
s->last_mv[1][0][1]= 0;
}
+/**
+ * finds the next resync_marker
+ * @param p pointer to buffer to scan
+ * @param end pointer to the end of the buffer
+ * @return pointer to the next resync_marker, or \p end if none was found
+ */
+const uint8_t *ff_h263_find_resync_marker(const uint8_t *restrict p, const uint8_t * restrict end)
+{
+ assert(p < end);
+
+ end-=2;
+ p++;
+ for(;p<end; p+=2){
+ if(!*p){
+ if (!p[-1] && p[1]) return p - 1;
+ else if(!p[ 1] && p[2]) return p;
+ }
+ }
+ return end+2;
+}
+
/**
* decodes the group of blocks / video packet header.
* @return bit position of the resync_marker, or <0 if none was found
diff --git a/libavcodec/mpegvideo.h b/libavcodec/mpegvideo.h
index 32ad5f4c6ca..453285e317e 100644
--- a/libavcodec/mpegvideo.h
+++ b/libavcodec/mpegvideo.h
@@ -836,6 +836,7 @@ void ff_clean_h263_qscales(MpegEncContext *s);
int ff_mpeg4_decode_partitions(MpegEncContext *s);
int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s);
int ff_h263_resync(MpegEncContext *s);
+const uint8_t *ff_h263_find_resync_marker(const uint8_t *p, const uint8_t *end);
int ff_h263_get_gob_height(MpegEncContext *s);
void ff_mpeg4_init_direct_mv(MpegEncContext *s);
int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my);
--
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