First stab at porting mplex

Original commit message from CVS:
First stab at porting mplex

1 files changed, 382 insertions, 0 deletions

diff --git a/ext/mplex/ac3strm_in.cc b/ext/mplex/ac3strm_in.cc
new file mode 100644
index 00000000..5dfc22d1
--- /dev/null
+++ b/ext/mplex/ac3strm_in.cc
@@ -0,0 +1,382 @@
+/*
+ *  ac3strm_in.c: AC3 Audio strem class members handling scanning and
+ *  buffering raw input stream.
+ *
+ *  Copyright (C) 2001 Andrew Stevens <andrew.stevens@philips.com>
+ *  Copyright (C) 2000,2001 Brent Byeler for original header-structure
+ *                          parsing code.
+ *
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of version 2 of the GNU General Public License
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#include <config.h>
+#include <math.h>
+#include <stdlib.h>
+
+#include "audiostrm.hh"
+#include "outputstream.hh"
+
+
+
+#define AC3_SYNCWORD            0x0b77
+#define AC3_PACKET_SAMPLES      1536
+
+/// table for the available AC3 bitrates
+static const unsigned int ac3_bitrate_index[32] = 
+{ 
+  32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192,
+  224, 256, 320, 384, 448, 512, 576, 640,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+static const unsigned int ac3_frame_size[3][32] = 
+{
+  {64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384,
+   448, 512, 640, 768, 896, 1024, 1152, 1280,
+   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+  {69, 87, 104, 121, 139, 174, 208, 243, 278, 348, 417,
+   487, 557, 696, 835, 975, 1114, 1253, 1393,
+   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+  {96, 120, 144, 168, 192, 240, 288, 336, 384, 480, 576,
+   672, 768, 960, 1152, 1344, 1536, 1728, 1920,
+   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
+};
+
+/// table for the available AC3 frequencies
+static const unsigned int ac3_frequency[4] = { 48000, 44100, 32000, 0 };
+
+
+AC3Stream::AC3Stream (IBitStream & ibs, OutputStream & into):
+AudioStream (ibs, into)
+{
+}
+
+bool
+AC3Stream::Probe (IBitStream & bs)
+{
+  return bs.getbits (16) == AC3_SYNCWORD;
+}
+
+
+/*************************************************************************
+ *
+ * Reads initial stream parameters and displays feedback banner to users
+ * @param stream_num AC3 substream ID
+ *************************************************************************/
+
+
+void
+AC3Stream::Init (const int stream_num)
+{
+  unsigned int framesize_code;
+
+  this->stream_num = stream_num;
+
+  MuxStream::Init (PRIVATE_STR_1, 1,	// Buffer scale
+		   default_buffer_size,
+		   muxinto.vcd_zero_stuffing,
+		   muxinto.buffers_in_audio, muxinto.always_buffers_in_audio);
+  mjpeg_info ("Scanning for header info: AC3 Audio stream %02x", stream_num);
+
+  InitAUbuffer ();
+  AU_start = bs.bitcount ();
+  if (bs.getbits (16) == AC3_SYNCWORD) {
+    num_syncword++;
+    bs.getbits (16);		// CRC field
+    frequency = bs.getbits (2);	// Sample rate code
+    framesize_code = bs.getbits (6);	// Frame size code
+    framesize = ac3_frame_size[frequency][framesize_code >> 1];
+    framesize = (framesize_code & 1) && frequency == 1 ? (framesize + 1) << 1 : (framesize << 1);
+
+
+    size_frames[0] = framesize;
+    size_frames[1] = framesize;
+    num_frames[0]++;
+    access_unit.start = AU_start;
+    access_unit.length = framesize;
+    bit_rate = ac3_bitrate_index[framesize_code >> 1];
+    samples_per_second = ac3_frequency[frequency];
+
+
+    /* Presentation time-stamping  */
+    access_unit.PTS = static_cast < clockticks > (decoding_order) *
+      static_cast < clockticks > (AC3_PACKET_SAMPLES) *
+      static_cast < clockticks > (CLOCKS) / samples_per_second;
+    access_unit.DTS = access_unit.PTS;
+    access_unit.dorder = decoding_order;
+    ++decoding_order;
+    aunits.append (access_unit);
+
+  } else {
+    mjpeg_error ("Invalid AC3 Audio stream header.");
+    exit (1);
+  }
+
+  OutputHdrInfo ();
+}
+
+/// @returns the current bitrate
+unsigned int
+AC3Stream::NominalBitRate ()
+{
+  return bit_rate;
+}
+
+/// Prefills the internal buffer for output multiplexing.
+/// @param frames_to_buffer the number of audio frames to read ahead
+void
+AC3Stream::FillAUbuffer (unsigned int frames_to_buffer)
+{
+  unsigned int framesize_code;
+
+  last_buffered_AU += frames_to_buffer;
+  mjpeg_debug ("Scanning %d MPEG audio frames to frame %d", frames_to_buffer, last_buffered_AU);
+
+  static int header_skip = 5;	// Initially skipped past  5 bytes of header 
+  int skip;
+  bool bad_last_frame = false;
+
+  while (!bs.eos () &&
+	 decoding_order < last_buffered_AU) {
+    skip = access_unit.length - header_skip;
+    if (skip & 0x1)
+      bs.getbits (8);
+    if (skip & 0x2)
+      bs.getbits (16);
+    skip = skip >> 2;
+
+    for (int i = 0; i < skip; i++) {
+      bs.getbits (32);
+    }
+
+    prev_offset = AU_start;
+    AU_start = bs.bitcount ();
+    if (AU_start - prev_offset != access_unit.length * 8) {
+      bad_last_frame = true;
+      break;
+    }
+
+    /* Check we have reached the end of have  another catenated 
+       stream to process before finishing ... */
+    if ((syncword = bs.getbits (16)) != AC3_SYNCWORD) {
+      if (!bs.eos ()) {
+	mjpeg_error_exit1 ("Can't find next AC3 frame - broken bit-stream?");
+      }
+      break;
+    }
+
+    bs.getbits (16);		// CRC field
+    bs.getbits (2);		// Sample rate code TOOD: check for change!
+    framesize_code = bs.getbits (6);
+    framesize = ac3_frame_size[frequency][framesize_code >> 1];
+    framesize = (framesize_code & 1) && frequency == 1 ? (framesize + 1) << 1 : (framesize << 1);
+
+    access_unit.start = AU_start;
+    access_unit.length = framesize;
+    access_unit.PTS = static_cast < clockticks > (decoding_order) *
+      static_cast < clockticks > (AC3_PACKET_SAMPLES) *
+      static_cast < clockticks > (CLOCKS) / samples_per_second;;
+    access_unit.DTS = access_unit.PTS;
+    access_unit.dorder = decoding_order;
+    decoding_order++;
+    aunits.append (access_unit);
+    num_frames[0]++;
+
+    num_syncword++;
+
+
+#ifdef DEBUG_AC3_HEADERS
+    /* Some stuff to generate frame-header information */
+    printf ("bsid       = %d\n", bs.getbits (5));
+    printf ("bsmode     = 0x%1x\n", bs.getbits (3));
+    int acmode = bs.getbits (3);
+
+    printf ("acmode     = 0x%1x\n", acmode);
+    if ((acmode & 0x1) && (acmode != 1))
+      printf ("cmixlev   = %d\n", bs.getbits (2));
+    if ((acmode & 0x4))
+      printf ("smixlev   = %d\n", bs.getbits (2));
+    if (acmode == 2)
+      printf ("dsurr     = %d\n", bs.getbits (2));
+    printf ("lfeon      = %d\n", bs.getbits (1));
+    printf ("dialnorm   = %02d\n", bs.getbits (5));
+    int compre = bs.getbits (1);
+
+    printf ("compre     = %d\n", compre);
+    if (compre)
+      printf ("compr    = %02d\n", bs.getbits (8));
+    int langcode = bs.getbits (1);
+
+    printf ("langcode     = %d\n", langcode);
+    if (langcode)
+      printf ("langcod  = 0x%02x\n", bs.getbits (8));
+
+    while (bs.bitcount () % 8 != 0)
+      bs.getbits (1);
+    header_skip = (bs.bitcount () - AU_start) / 8;
+#endif
+    if (num_syncword >= old_frames + 10) {
+      mjpeg_debug ("Got %d frame headers.", num_syncword);
+      old_frames = num_syncword;
+    }
+
+
+  }
+  if (bad_last_frame) {
+    mjpeg_error_exit1 ("Last AC3 frame ended prematurely!\n");
+  }
+  last_buffered_AU = decoding_order;
+  eoscan = bs.eos ();
+
+}
+
+
+/// Closes the AC3 stream and prints some statistics.
+void
+AC3Stream::Close ()
+{
+  stream_length = AU_start >> 3;
+  mjpeg_info ("AUDIO_STATISTICS: %02x", stream_id);
+  mjpeg_info ("Audio stream length %lld bytes.", stream_length);
+  mjpeg_info ("Syncwords      : %8u", num_syncword);
+  mjpeg_info ("Frames         : %8u padded", num_frames[0]);
+  mjpeg_info ("Frames         : %8u unpadded", num_frames[1]);
+
+  bs.close ();
+}
+
+/*************************************************************************
+	OutputAudioInfo
+	gibt gesammelte Informationen zu den Audio Access Units aus.
+
+	Prints information on audio access units
+*************************************************************************/
+
+void
+AC3Stream::OutputHdrInfo ()
+{
+  mjpeg_info ("AC3 AUDIO STREAM:");
+
+  mjpeg_info ("Bit rate       : %8u bytes/sec (%3u kbit/sec)", bit_rate * 128, bit_rate);
+
+  if (frequency == 3)
+    mjpeg_info ("Frequency      : reserved");
+  else
+    mjpeg_info ("Frequency      :     %d Hz", ac3_frequency[frequency]);
+
+}
+
+/**
+Reads the bytes neccessary to complete the current packet payload. 
+@param to_read number of bytes to read
+@param dst byte buffer pointer to read to 
+@returns the number of bytes read
+ */
+unsigned int
+AC3Stream::ReadPacketPayload (uint8_t * dst, unsigned int to_read)
+{
+  static unsigned int aus = 0;
+  static unsigned int rd = 0;
+
+  unsigned int bytes_read = bs.read_buffered_bytes (dst + 4, to_read - 4);
+
+  rd += bytes_read;
+  clockticks decode_time;
+
+  unsigned int first_header = (new_au_next_sec || au_unsent > bytes_read)
+    ? 0 : au_unsent;
+
+  // BUG BUG BUG: how do we set the 1st header pointer if we have
+  // the *middle* part of a large frame?
+  assert (first_header <= to_read - 2);
+
+
+  unsigned int syncwords = 0;
+  unsigned int bytes_muxed = bytes_read;
+
+  if (bytes_muxed == 0 || MuxCompleted ()) {
+    goto completion;
+  }
+
+
+  /* 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.
+
+   */
+
+  decode_time = RequiredDTS ();
+  while (au_unsent < bytes_muxed) {
+    // BUG BUG BUG: if we ever had odd payload / packet size we might
+    // split an AC3 frame in the middle of the syncword!
+    assert (bytes_muxed > 1);
+    bufmodel.Queued (au_unsent, decode_time);
+    bytes_muxed -= au_unsent;
+    if (new_au_next_sec)
+      ++syncwords;
+    aus += au->length;
+    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 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) {
+    if (new_au_next_sec)
+      ++syncwords;
+    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)
+      ++syncwords;
+    aus += au->length;
+    new_au_next_sec = NextAU ();
+  }
+completion:
+  // Generate the AC3 header...
+  // Note the index counts from the low byte of the offset so
+  // the smallest value is 1!
+
+  dst[0] = AC3_SUB_STR_0 + stream_num;
+  dst[1] = syncwords;
+  dst[2] = (first_header + 1) >> 8;
+  dst[3] = (first_header + 1) & 0xff;
+
+  return bytes_read + 4;
+}
+
+
+
+/* 
+ * Local variables:
+ *  c-file-style: "stroustrup"
+ *  tab-width: 4
+ *  indent-tabs-mode: nil
+ * End:
+ */