void ElementaryStream::Muxed (unsigned int bytes_muxed)
{
clockticks decode_time;
if (bytes_muxed == 0 || MuxCompleted() )
return;
/* Work through what's left of the current AU and the following AU's
updating the info until we reach a point where an AU had to be
split between packets.
NOTE: It *is* possible for this loop to iterate.
The DTS/PTS field for the packet in this case would have been
given the that for the first AU to start in the packet.
Whether Joe-Blow's hardware VCD player handles this properly is
another matter of course!
*/
decode_time = RequiredDTS();
while (au_unsent < bytes_muxed)
{
AUMuxed(true); // Update stream specific tracking
// of AUs muxed...
bufmodel.Queued(au_unsent, decode_time);
bytes_muxed -= au_unsent;
new_au_next_sec = NextAU();
if( !new_au_next_sec )
return;
decode_time = RequiredDTS();
};
// We've now reached a point where the current AU overran or
// fitted exactly. We need to distinguish the latter case
// so we can record whether the next packet starts with an
// existing AU or not - info we need to decide what PTS/DTS
// info to write at the start of the next packet.
if (au_unsent > bytes_muxed)
{
AUMuxed(false);
bufmodel.Queued( bytes_muxed, decode_time);
au_unsent -= bytes_muxed;
new_au_next_sec = false;
}
else // if (au_unsent == bytes_muxed)
{
AUMuxed(false);
bufmodel.Queued(bytes_muxed, decode_time);
new_au_next_sec = NextAU();
}
}
unsigned int
LPCMStream::ReadPacketPayload(uint8_t *dst, unsigned int to_read)
{
unsigned int header_size = LPCMStream::StreamHeaderSize();
bitcount_t read_start = bs.GetBytePos();
unsigned int bytes_read = bs.GetBytes( dst+header_size,
to_read-header_size );
bs.Flush( read_start );
clockticks decode_time;
bool starting_frame_found = false;
uint8_t starting_frame_index = 0;
int starting_frame_offset =
(new_au_next_sec || au_unsent > bytes_read )
? 0
: au_unsent;
unsigned int frames = 0;
unsigned int bytes_muxed = bytes_read;
if (bytes_muxed == 0 || MuxCompleted() )
{
goto completion;
}
/* Work through what's left of the current frames and the
following frames's updating the info until we reach a point where
an frame had to be split between packets.
The DTS/PTS field for the packet in this case would have been
given the that for the first AU to start in the packet.
*/
decode_time = RequiredDTS();
while (au_unsent < bytes_muxed)
{
assert( bytes_muxed > 1 );
bufmodel.Queued(au_unsent, decode_time);
bytes_muxed -= au_unsent;
if( new_au_next_sec )
{
++frames;
if( ! starting_frame_found )
{
starting_frame_index = static_cast<uint8_t>(au->dorder % 20);
starting_frame_found = true;
}
}
if( !NextAU() )
{
goto completion;
}
new_au_next_sec = true;
decode_time = RequiredDTS();
};
// We've now reached a point where the current AU overran or
// fitted exactly. We need to distinguish the latter case so we
// can record whether the next packet starts with the tail end of
// // an already started frame or a new one. We need this info to
// decide what PTS/DTS info to write at the start of the next
// packet.
if (au_unsent > bytes_muxed)
{
if( new_au_next_sec )
++frames;
bufmodel.Queued( bytes_muxed, decode_time);
au_unsent -= bytes_muxed;
new_au_next_sec = false;
}
else // if (au_unsent == bytes_muxed)
{
bufmodel.Queued(bytes_muxed, decode_time);
if( new_au_next_sec )
++frames;
new_au_next_sec = NextAU();
}
completion:
// Generate the LPCM header...
// Note the index counts from the low byte of the offset so
// the smallest value is 1!
dst[0] = LPCM_SUB_STR_0 + stream_num;
dst[1] = frames;
dst[2] = (starting_frame_offset+4)>>8;
dst[3] = (starting_frame_offset+4)&0xff;
unsigned int bps_code;
switch( bits_per_sample )
{
case 16 : bps_code = 0; break;
case 20 : bps_code = 1; break;
case 24 : bps_code = 2; break;
default : bps_code = 3; break;
}
dst[4] = starting_frame_index;
unsigned int bsf_code = (samples_per_second == 48000) ? 0 : 1;
unsigned int channels_code = channels - 1;
dst[5] = (bps_code << 6) | (bsf_code << 4) | channels_code;
dst[6] = dynamic_range_code;
return bytes_read+header_size;
}
