[FFmpeg-devel] [PATCH] avformat/avidec: use avpriv_find_start_code in avi_read_packet()

[zhaoxiu.zeng]

>From 50cefc3b62bf45e16b858f5e414777afb1a9bd36 Mon Sep 17 00:00:00 2001
From: Zeng Zhaoxiu <zhaoxiu.zeng at gmail.com>
Date: Sun, 15 Mar 2015 11:54:13 +0800
Subject: [PATCH 1/7] avformat/avidec: use avpriv_find_start_code in
 avi_read_packet()

Signed-off-by: Zeng Zhaoxiu <zhaoxiu.zeng at gmail.com>
---
 libavformat/avidec.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index 00f0037..42599bf 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -36,7 +36,8 @@
 #include "riff.h"
 #include "libavcodec/bytestream.h"
 #include "libavcodec/exif.h"
-#include "libavformat/isom.h"
+#include "libavcodec/internal.h"
+#include "isom.h"
 
 typedef struct AVIStream {
     int64_t frame_offset;   /* current frame (video) or byte (audio) counter
@@ -1444,19 +1445,17 @@ FF_ENABLE_DEPRECATION_WARNINGS
                 e     = &st->index_entries[index];
 
                 if (index >= 0 && e->timestamp == ast->frame_offset) {
-                    if (index == st->nb_index_entries-1) {
-                        int key=1;
-                        int i;
-                        uint32_t state=-1;
-                        for (i=0; i<FFMIN(size,256); i++) {
-                            if (st->codec->codec_id == AV_CODEC_ID_MPEG4) {
-                                if (state == 0x1B6) {
-                                    key= !(pkt->data[i]&0xC0);
-                                    break;
-                                }
-                            }else
+                    if (index == st->nb_index_entries - 1 &&
+                        st->codec->codec_id == AV_CODEC_ID_MPEG4) {
+                        const uint8_t *ptr = pkt->data, *end = ptr + FFMIN(size, 256);
+                        int key = 1;
+                        uint32_t state = -1;
+                        while (ptr < end) {
+                            ptr = avpriv_find_start_code(ptr, end, &state);
+                            if (state == 0x1B6 && ptr < end) {
+                                key = !(*ptr & 0xC0);
                                 break;
-                            state= (state<<8) + pkt->data[i];
+                            }
                         }
                         if (!key)
                             e->flags &= ~AVINDEX_KEYFRAME;
-- 
2.1.0