mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-11-19 08:11:16 +00:00
383 lines
11 KiB
C++
383 lines
11 KiB
C++
/*
|
||
* 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"
|
||
#include <cassert>
|
||
|
||
|
||
|
||
#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 %d bytes.", (int)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:
|
||
*/
|