@@ -202,10 +202,10 @@ static int scan_mmco_reset(AVCodecParserContext *s)

  */

 static inline int parse_nal_units(AVCodecParserContext *s,

                                   AVCodecContext *avctx,

-                                  const uint8_t *buf, int buf_size)

+                                  const uint8_t * const buf, int buf_size)

 {

     H264Context *h         = s->priv_data;

-    const uint8_t *buf_end = buf + buf_size;

+    int buf_index, next_avc;

     unsigned int pps_id;

     unsigned int slice_type;

     int state = -1, got_reset = 0;

@@ -225,26 +225,26 @@ static inline int parse_nal_units(AVCodecParserContext *s,

     if (!buf_size)

         return 0;

+    buf_index     = 0;

+    next_avc      = h->is_avc ? 0 : buf_size;

     for (;;) {

         int src_length, dst_length, consumed, nalsize = 0;

-        if (h->is_avc) {

-            int i;

-            if (h->nal_length_size >= buf_end - buf) break;

-            nalsize = 0;

-            for (i = 0; i < h->nal_length_size; i++)

-                nalsize = (nalsize << 8) | *buf++;

-            if (nalsize <= 0 || nalsize > buf_end - buf) {

-                av_log(h->avctx, AV_LOG_ERROR, "AVC: nal size %d\n", nalsize);

+

+        if (buf_index >= next_avc) {

+            nalsize = get_avc_nalsize(h, buf, buf_size, &buf_index);

+            if (nalsize < 0)

                 break;

-            }

-            src_length = nalsize;

+            next_avc = buf_index + nalsize;

         } else {

-        buf = avpriv_find_start_code(buf, buf_end, &state);

-        if (buf >= buf_end)

-            break;

-        --buf;

-        src_length = buf_end - buf;

+            buf_index = find_start_code(buf, buf_size, buf_index, next_avc);

+            if (buf_index >= buf_size)

+                break;

+            if (buf_index >= next_avc)

+                continue;

         }

+        src_length = next_avc - buf_index;

+

+        state = buf[buf_index];

         switch (state & 0x1f) {

         case NAL_SLICE:

         case NAL_IDR_SLICE:

@@ -261,10 +261,13 @@ static inline int parse_nal_units(AVCodecParserContext *s,

             }

             break;

         }

-        ptr = ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);

+        ptr = ff_h264_decode_nal(h, buf + buf_index, &dst_length,

+                                 &consumed, src_length);

         if (!ptr || dst_length < 0)

             break;

+        buf_index += consumed;

+

         init_get_bits(&h->gb, ptr, 8 * dst_length);

         switch (h->nal_unit_type) {

         case NAL_SPS:

@@ -439,7 +442,6 @@ static inline int parse_nal_units(AVCodecParserContext *s,

             return 0; /* no need to evaluate the rest */

         }

-        buf += h->is_avc ? nalsize : consumed;

     }

     if (q264)

         return 0;