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authorIan Caulfield <ian.caulfield@gmx.at>2007-01-24 15:31:48 +0000
committerGuillaume Poirier <gpoirier@mplayerhq.hu>2007-01-24 15:31:48 +0000
commit44a39bd7701e71e0713e67efcc27f3aa0b456417 (patch)
treebb8ad1c895889b94ee8e5d71468e17c28f9f780f /libavcodec
parent6ad7cd0469989529e4bb0d469ab5f1978dd1c201 (diff)
downloadffmpeg-44a39bd7701e71e0713e67efcc27f3aa0b456417.tar.gz
Allows the AC3 parser to read the frame size and codec parameters from E-AC3 streams,
allowing them to be correctly demuxed. Currently it only identifies the primary substream, and will skip over any additional dependent or independent substreams. Patch by Ian Caulfield % ian P caulfield A gmail P com % Original thread: date: Jan 19, 2007 9:55 AM subject: Re: [Ffmpeg-devel] [PATCH] Correctly parse headers of E-AC3 streams Originally committed as revision 7687 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec')
-rw-r--r--libavcodec/parser.c51
1 files changed, 46 insertions, 5 deletions
diff --git a/libavcodec/parser.c b/libavcodec/parser.c
index 740ad855c4..faeb5ff815 100644
--- a/libavcodec/parser.c
+++ b/libavcodec/parser.c
@@ -632,9 +632,14 @@ static const int ac3_bitrates[64] = {
384, 448, 448, 512, 512, 576, 576, 640, 640,
};
-static const int ac3_channels[8] = {
+static const uint8_t ac3_channels[8] = {
2, 1, 2, 3, 3, 4, 4, 5
};
+
+static const uint8_t eac3_blocks[4] = {
+ 1, 2, 3, 6
+};
+
#endif /* CONFIG_AC3_PARSER */
#ifdef CONFIG_AAC_PARSER
@@ -653,6 +658,7 @@ static int ac3_sync(const uint8_t *buf, int *channels, int *sample_rate,
int *bit_rate, int *samples)
{
unsigned int fscod, frmsizecod, acmod, bsid, lfeon;
+ unsigned int strmtyp, substreamid, frmsiz, fscod2, numblkscod;
GetBitContext bits;
init_get_bits(&bits, buf, AC3_HEADER_SIZE * 8);
@@ -660,16 +666,16 @@ static int ac3_sync(const uint8_t *buf, int *channels, int *sample_rate,
if(get_bits(&bits, 16) != 0x0b77)
return 0;
+ bsid = show_bits_long(&bits, 29) & 0x1f;
+ if(bsid <= 8) { /* Normal AC-3 */
skip_bits(&bits, 16); /* crc */
fscod = get_bits(&bits, 2);
frmsizecod = get_bits(&bits, 6);
- if(!ac3_sample_rates[fscod])
+ if(fscod == 3)
return 0;
- bsid = get_bits(&bits, 5);
- if(bsid > 8)
- return 0;
+ skip_bits(&bits, 5); /* bsid */
skip_bits(&bits, 3); /* bsmod */
acmod = get_bits(&bits, 3);
if(acmod & 1 && acmod != 1)
@@ -686,6 +692,41 @@ static int ac3_sync(const uint8_t *buf, int *channels, int *sample_rate,
*samples = 6 * 256;
return ac3_frame_sizes[frmsizecod][fscod] * 2;
+ } else if (bsid >= 10 && bsid <= 16) { /* Enhanced AC-3 */
+ strmtyp = get_bits(&bits, 2);
+ substreamid = get_bits(&bits, 3);
+
+ if (strmtyp != 0 || substreamid != 0)
+ return 0; /* Currently don't support additional streams */
+
+ frmsiz = get_bits(&bits, 11) + 1;
+ fscod = get_bits(&bits, 2);
+ if (fscod == 3) {
+ fscod2 = get_bits(&bits, 2);
+ numblkscod = 3;
+
+ if(fscod2 == 3)
+ return 0;
+
+ *sample_rate = ac3_sample_rates[fscod2] / 2;
+ } else {
+ numblkscod = get_bits(&bits, 2);
+
+ *sample_rate = ac3_sample_rates[fscod];
+ }
+
+ acmod = get_bits(&bits, 3);
+ lfeon = get_bits1(&bits);
+
+ *samples = eac3_blocks[numblkscod] * 256;
+ *bit_rate = frmsiz * (*sample_rate) * 16 / (*samples);
+ *channels = ac3_channels[acmod] + lfeon;
+
+ return frmsiz * 2;
+ }
+
+ /* Unsupported bitstream version */
+ return 0;
}
#endif /* CONFIG_AC3_PARSER */