From 9922584ba3b5b02d913e629ea74d72e994870873 Mon Sep 17 00:00:00 2001
From: John Stebbins <jstebbins.hb@gmail.com>
Date: Thu, 17 Jan 2013 19:57:26 +0100
Subject: [PATCH] dca_parser: Handle changes in dca frame size

A change in framesize caused a perpetual loss of synchronization.
So read (and use) the frame size from the frame header instead of
setting it only once.
---
 libavcodec/dca_parser.c |   15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/libavcodec/dca_parser.c b/libavcodec/dca_parser.c
index ab235cf..12180f3 100644
--- a/libavcodec/dca_parser.c
+++ b/libavcodec/dca_parser.c
@@ -62,10 +62,12 @@ static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,
             if (IS_MARKER(state, i, buf, buf_size)) {
                 if (pc1->lastmarker && state == pc1->lastmarker) {
                     start_found = 1;
+                    i++;
                     break;
                 } else if (!pc1->lastmarker) {
                     start_found = 1;
                     pc1->lastmarker = state;
+                    i++;
                     break;
                 }
             }
@@ -80,9 +82,6 @@ static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,
             if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) {
                 if(pc1->framesize > pc1->size)
                     continue;
-                if(!pc1->framesize){
-                    pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size;
-                }
                 pc->frame_start_found = 0;
                 pc->state = -1;
                 pc1->size = 0;
@@ -139,7 +138,7 @@ int ff_dca_convert_bitstream(const uint8_t *src, int src_size, uint8_t *dst,
 }
 
 static int dca_parse_params(const uint8_t *buf, int buf_size, int *duration,
-                            int *sample_rate)
+                            int *sample_rate, int *framesize)
 {
     GetBitContext gb;
     uint8_t hdr[12 + FF_INPUT_BUFFER_PADDING_SIZE] = { 0 };
@@ -159,7 +158,11 @@ static int dca_parse_params(const uint8_t *buf, int buf_size, int *duration,
         return AVERROR_INVALIDDATA;
     *duration = 256 * (sample_blocks / 8);
 
-    skip_bits(&gb, 20);
+    *framesize = get_bits(&gb, 14) + 1;
+    if (*framesize < 95)
+        return AVERROR_INVALIDDATA;
+
+    skip_bits(&gb, 6);
     sr_code = get_bits(&gb, 4);
     *sample_rate = avpriv_dca_sample_rates[sr_code];
     if (*sample_rate == 0)
@@ -190,7 +193,7 @@ static int dca_parse(AVCodecParserContext * s,
     }
 
     /* read the duration and sample rate from the frame header */
-    if (!dca_parse_params(buf, buf_size, &duration, &sample_rate)) {
+    if (!dca_parse_params(buf, buf_size, &duration, &sample_rate, &pc1->framesize)) {
         s->duration = duration;
         avctx->sample_rate = sample_rate;
     } else
-- 
1.7.10.4