public static void Scan(
TSAudioStream stream,
TSStreamBuffer buffer,
long bitrate,
ref string tag)
{
if (stream.IsInitialized) return;
bool syncFound = false;
uint sync = 0;
for (int i = 0; i < buffer.Length; i++)
{
sync = (sync << 8) + buffer.ReadByte();
if (sync == 0x7FFE8001)
{
syncFound = true;
break;
}
}
if (!syncFound) return;
int frame_type = buffer.ReadBits(1);
int samples_deficit = buffer.ReadBits(5);
int crc_present = buffer.ReadBits(1);
int sample_blocks = buffer.ReadBits(7);
int frame_size = buffer.ReadBits(14);
if (frame_size < 95)
{
return;
}
int amode = buffer.ReadBits(6);
int sample_rate = buffer.ReadBits(4);
if (sample_rate < 0 || sample_rate >= dca_sample_rates.Length)
{
return;
}
int bit_rate = buffer.ReadBits(5);
if (bit_rate < 0 || bit_rate >= dca_bit_rates.Length)
{
return;
}
int downmix = buffer.ReadBits(1);
int dynrange = buffer.ReadBits(1);
int timestamp = buffer.ReadBits(1);
int aux_data = buffer.ReadBits(1);
int hdcd = buffer.ReadBits(1);
int ext_descr = buffer.ReadBits(3);
int ext_coding = buffer.ReadBits(1);
int aspf = buffer.ReadBits(1);
int lfe = buffer.ReadBits(2);
int predictor_history = buffer.ReadBits(1);
if (crc_present == 1)
{
int crc = buffer.ReadBits(16);
}
int multirate_inter = buffer.ReadBits(1);
int version = buffer.ReadBits(4);
int copy_history = buffer.ReadBits(2);
int source_pcm_res = buffer.ReadBits(3);
int front_sum = buffer.ReadBits(1);
int surround_sum = buffer.ReadBits(1);
int dialog_norm = buffer.ReadBits(4);
if (source_pcm_res < 0 || source_pcm_res >= dca_bits_per_sample.Length)
{
return;
}
int subframes = buffer.ReadBits(4);
int total_channels = buffer.ReadBits(3) + 1 + ext_coding;
stream.SampleRate = dca_sample_rates[sample_rate];
stream.ChannelCount = total_channels;
stream.LFE = (lfe > 0 ? 1 : 0);
stream.BitDepth = dca_bits_per_sample[source_pcm_res];
stream.DialNorm = -dialog_norm;
if ((source_pcm_res & 0x1) == 0x1)
{
stream.AudioMode = TSAudioMode.Extended;
}
stream.BitRate = (uint)dca_bit_rates[bit_rate];
switch (stream.BitRate)
{
case 1:
if (bitrate > 0)
{
stream.BitRate = bitrate;
stream.IsVBR = false;
stream.IsInitialized = true;
}
else
{
stream.BitRate = 0;
}
break;
case 2:
case 3:
stream.IsVBR = true;
stream.IsInitialized = true;
break;
default:
stream.IsVBR = false;
stream.IsInitialized = true;
break;
}
}