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Code Issues Releases Activity

added DVD LPCM decoding support

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Originally committed as revision 1525 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Fabrice Bellard 2003-01-31 17:04:46 +00:00
parent f17457ac49
commit 9ec05e3680
1 changed files with 20 additions and 0 deletions
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20
libavformat/mpeg.c
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@ -598,6 +598,9 @@ static int mpegps_read_packet(AVFormatContext *s,
} else if (startcode >= 0x80 && startcode <= 0x9f) {
type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_AC3;
} else if (startcode >= 0xa0 && startcode <= 0xbf) {
type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_PCM_S16BE;
} else {
skip:
/* skip packet */
@ -611,6 +614,23 @@ static int mpegps_read_packet(AVFormatContext *s,
st->codec.codec_type = type;
st->codec.codec_id = codec_id;
found:
if (startcode >= 0xa0 && startcode <= 0xbf) {
int b1, freq;
static const int lpcm_freq_tab[4] = { 48000, 96000, 44100, 32000 };
/* for LPCM, we just skip the header and consider it is raw
audio data */
if (len <= 3)
goto skip;
get_byte(&s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
b1 = get_byte(&s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
get_byte(&s->pb); /* dynamic range control (0x80 = off) */
len -= 3;
freq = (b1 >> 4) & 3;
st->codec.sample_rate = lpcm_freq_tab[freq];
st->codec.channels = 1 + (b1 & 7);
st->codec.bit_rate = st->codec.channels * st->codec.sample_rate * 2;
}
av_new_packet(pkt, len);
//printf("\nRead Packet ID: %x PTS: %f Size: %d", startcode,
// (float)pts/90000, len);