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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
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