[FFmpeg-devel] [PATCH] avformat/mpegvideodec: use avpriv_find_start_code in mpegvideo_probe()

[zhaoxiu.zeng]

>From 60cdc9161881cdf86e428a0d6812785938ae6667 Mon Sep 17 00:00:00 2001
From: Zeng Zhaoxiu <zhaoxiu.z...@gmail.com>
Date: Sun, 15 Mar 2015 11:56:53 +0800
Subject: [PATCH 2/7] avformat/mpegvideodec: use avpriv_find_start_code in
 mpegvideo_probe()

Signed-off-by: Zeng Zhaoxiu <zhaoxiu.z...@gmail.com>
---
 libavformat/mpegvideodec.c | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/libavformat/mpegvideodec.c b/libavformat/mpegvideodec.c
index ade76d8..c2fa6c2 100644
--- a/libavformat/mpegvideodec.c
+++ b/libavformat/mpegvideodec.c
@@ -24,6 +24,7 @@
 #include "rawdec.h"
 
 #include "libavutil/intreadwrite.h"
+#include "libavcodec/internal.h"
 
 #define SEQ_START_CODE          0x000001b3
 #define GOP_START_CODE          0x000001b8
@@ -37,33 +38,30 @@ static int mpegvideo_probe(AVProbeData *p)
 {
     uint32_t code= -1;
     int pic=0, seq=0, slice=0, pspack=0, vpes=0, apes=0, res=0, sicle=0;
-    int i, j;
+    const uint8_t *ptr = p->buf, *end = ptr + p->buf_size;
     uint32_t last = 0;
+    int j;
 
-    for(i=0; i<p->buf_size; i++){
-        code = (code<<8) + p->buf[i];
+    while (ptr < end) {
+        ptr = avpriv_find_start_code(ptr, end, &code);
         if ((code & 0xffffff00) == 0x100) {
-            switch(code){
+            switch (code) {
             case     SEQ_START_CODE:
-                if (!(p->buf[i+1+3+1+2] & 0x20))
+                if (!(ptr[3 + 1 + 2] & 0x20))
                     break;
-                j = i;
-                if (p->buf[j+8] & 2)
-                    j+= 64;
-                if (j >= p->buf_size)
+                j = -1 + (ptr[-1 + 8] & 2) * 32;
+                if (ptr + j >= end)
                     break;
-                if (p->buf[j+8] & 1)
-                    j+= 64;
-                if (j >= p->buf_size)
+                j += (ptr[j + 8] & 1) * 64;
+                if (ptr + j >= end)
                     break;
-                if (AV_RB24(p->buf + j + 9) & 0xFFFFFE)
+                if (AV_RB24(ptr + j + 9) & 0xFFFFFE)
                     break;
                 seq++;
-            break;
-            case PICTURE_START_CODE:   pic++; break;
+                break;
+            case PICTURE_START_CODE:    pic++; break;
             case    PACK_START_CODE: pspack++; break;
-            case              0x1b6:
-                                        res++; break;
+            case              0x1b6:    res++; break;
             }
             if (code >= SLICE_START_CODE && code <= 0x1af) {
                 if (last >= SLICE_START_CODE && last <= 0x1af) {
-- 
2.1.0

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