gstreamer/gst-libs/ext/mplex/videostrm_in.cc

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/*
* inptstrm.c: Members of video stream class related to raw stream
* scanning and buffering.
*
* Copyright (C) 2001 Andrew Stevens <andrew.stevens@philips.com>
*
*
* 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 "videostrm.hh"
#include "outputstream.hh"
static void
marker_bit (IBitStream & bs, unsigned int what)
{
if (what != bs.get1bit ()) {
mjpeg_error ("Illegal MPEG stream at offset (bits) %lld: supposed marker bit not found.",
bs.bitcount ());
exit (1);
}
}
void
VideoStream::ScanFirstSeqHeader ()
{
if (bs.getbits (32) == SEQUENCE_HEADER) {
num_sequence++;
horizontal_size = bs.getbits (12);
vertical_size = bs.getbits (12);
aspect_ratio = bs.getbits (4);
pict_rate = bs.getbits (4);
picture_rate = pict_rate;
bit_rate = bs.getbits (18);
marker_bit (bs, 1);
vbv_buffer_size = bs.getbits (10);
CSPF = bs.get1bit ();
} else {
mjpeg_error ("Invalid MPEG Video stream header.");
exit (1);
}
if (pict_rate > 0 && pict_rate <= mpeg_num_framerates) {
frame_rate = Y4M_RATIO_DBL (mpeg_framerate (pict_rate));
} else {
frame_rate = 25.0;
}
}
void
VideoStream::Init (const int stream_num)
{
mjpeg_debug ("SETTING video buffer to %d", muxinto.video_buffer_size);
MuxStream::Init (VIDEO_STR_0 + stream_num, 1, // Buffer scale
muxinto.video_buffer_size, 0, // Zero stuffing
muxinto.buffers_in_video, muxinto.always_buffers_in_video);
mjpeg_info ("Scanning for header info: Video stream %02x ", VIDEO_STR_0 + stream_num);
InitAUbuffer ();
ScanFirstSeqHeader ();
/* Skip to the end of the 1st AU (*2nd* Picture start!)
*/
AU_hdr = SEQUENCE_HEADER;
AU_pict_data = 0;
AU_start = 0LL;
OutputSeqhdrInfo ();
}
//
// Set the Maximum STD buffer delay for this video stream.
// By default we set 1 second but if we have specified a video
// buffer that can hold more than 1.0 seconds demuxed data we
// set the delay to the time to fill the buffer.
//
void
VideoStream::SetMaxStdBufferDelay (unsigned int dmux_rate)
{
double max_delay = CLOCKS;
if (static_cast < double >(BufferSize ()) / dmux_rate > 1.0)
max_delay *= static_cast < double >(BufferSize ()) / dmux_rate;
//
// To enforce a maximum STD buffer residency the
// calculation is a bit tricky as when we decide to mux we may
// (but not always) have some of the *previous* picture left to
// mux in which case it is the timestamp of the next picture that counts.
// For simplicity we simply reduce the limit by 1.5 frame intervals
// and use the timestamp for the current picture.
//
if (frame_rate > 10.0)
max_STD_buffer_delay = static_cast < clockticks > (max_delay * (frame_rate - 1.5) / frame_rate);
else
max_STD_buffer_delay = static_cast < clockticks > (10.0 * max_delay / frame_rate);
}
//
// Return whether AU buffer needs refilling. There are two cases:
// 1. We have less than our look-ahead "FRAME_CHUNK" buffer AU's
// buffered 2. AU's are very small and we could have less than 1
// sector's worth of data buffered.
//
bool
VideoStream::AUBufferNeedsRefill ()
{
return
!eoscan
&& (aunits.current () + FRAME_CHUNK > last_buffered_AU
|| bs.buffered_bytes () < muxinto.sector_size);
}
//
// Refill the AU unit buffer setting AU PTS DTS from the scanned
// header information...
//
void
VideoStream::FillAUbuffer (unsigned int frames_to_buffer)
{
if (eoscan)
return;
last_buffered_AU += frames_to_buffer;
mjpeg_debug ("Scanning %d video frames to frame %d", frames_to_buffer, last_buffered_AU);
// We set a limit of 2M to seek before we give up.
// This is intentionally very high because some heavily
// padded still frames may have a loooong gap before
// a following sequence end marker.
while (!bs.eos () &&
bs.seek_sync (SYNCWORD_START, 24, 2 * 1024 * 1024) &&
decoding_order < last_buffered_AU)
{
syncword = (SYNCWORD_START << 8) + bs.getbits (8);
if (AU_pict_data) {
/* Handle the header *ending* an AU...
If we have the AU picture data an AU and have now
reached a header marking the end of an AU fill in the
the AU length and append it to the list of AU's and
start a new AU. I.e. sequence and gop headers count as
part of the AU of the corresponding picture
*/
stream_length = bs.bitcount () - 32LL;
switch (syncword) {
case SEQUENCE_HEADER:
case GROUP_START:
case PICTURE_START:
access_unit.start = AU_start;
access_unit.length = (int) (stream_length - AU_start) >> 3;
access_unit.end_seq = 0;
avg_frames[access_unit.type - 1] += access_unit.length;
aunits.append (access_unit);
mjpeg_debug ("Found AU %d: DTS=%d", access_unit.dorder, (int) access_unit.DTS / 300);
AU_hdr = syncword;
AU_start = stream_length;
AU_pict_data = 0;
break;
case SEQUENCE_END:
access_unit.length = ((stream_length - AU_start) >> 3) + 4;
access_unit.end_seq = 1;
aunits.append (access_unit);
mjpeg_info ("Scanned to end AU %d", access_unit.dorder);
avg_frames[access_unit.type - 1] += access_unit.length;
/* Do we have a sequence split in the video stream? */
if (!bs.eos () && bs.getbits (32) == SEQUENCE_HEADER) {
stream_length = bs.bitcount () - 32LL;
AU_start = stream_length;
syncword = AU_hdr = SEQUENCE_HEADER;
AU_pict_data = 0;
if (opt_multifile_segment)
mjpeg_warn
("Sequence end marker found in video stream but single-segment splitting specified!");
} else {
if (!bs.eos () && !opt_multifile_segment)
mjpeg_warn ("No seq. header starting new sequence after seq. end!");
}
num_seq_end++;
break;
}
}
/* Handle the headers starting an AU... */
switch (syncword) {
case SEQUENCE_HEADER:
/* TODO: Really we should update the info here so we can handle
streams where parameters change on-the-fly... */
num_sequence++;
break;
case GROUP_START:
num_groups++;
group_order = 0;
break;
case PICTURE_START:
/* We have reached AU's picture data... */
AU_pict_data = 1;
prev_temp_ref = temporal_reference;
temporal_reference = bs.getbits (10);
access_unit.type = bs.getbits (3);
/* Now scan forward a little for an MPEG-2 picture coding extension
so we can get pulldown info (if present) */
if (bs.seek_sync (EXT_START_CODE, 32, 64) && bs.getbits (4) == CODING_EXT_ID) {
/* Skip: 4 F-codes (4)... */
(void) bs.getbits (16);
/* Skip: DC Precision(2) */
(void) bs.getbits (2);
pict_struct = bs.getbits (2);
/* Skip: topfirst (1) frame pred dct (1),
concealment_mv(1), q_scale_type (1), */
(void) bs.getbits (4);
/* Skip: intra_vlc_format(1), alternate_scan (1) */
(void) bs.getbits (2);
repeat_first_field = bs.getbits (1);
pulldown_32 |= repeat_first_field;
} else {
repeat_first_field = 0;
pict_struct = PIC_FRAME;
}
if (access_unit.type == IFRAME) {
unsigned int bits_persec =
(unsigned int) (((double) (stream_length - prev_offset)) *
2 * frame_rate / ((double) (2 + fields_presented - group_start_field)));
if (bits_persec > max_bits_persec) {
max_bits_persec = bits_persec;
}
prev_offset = stream_length;
group_start_pic = decoding_order;
group_start_field = fields_presented;
}
NextDTSPTS (access_unit.DTS, access_unit.PTS);
access_unit.dorder = decoding_order;
access_unit.porder = temporal_reference + group_start_pic;
access_unit.seq_header = (AU_hdr == SEQUENCE_HEADER);
decoding_order++;
group_order++;
if ((access_unit.type > 0) && (access_unit.type < 5)) {
num_frames[access_unit.type - 1]++;
}
if (decoding_order >= old_frames + 1000) {
mjpeg_debug ("Got %d picture headers.", decoding_order);
old_frames = decoding_order;
}
break;
}
}
last_buffered_AU = decoding_order;
num_pictures = decoding_order;
eoscan = bs.eos ();
}
void
VideoStream::Close ()
{
bs.close ();
stream_length = (unsigned int) (AU_start / 8);
for (int i = 0; i < 4; i++) {
avg_frames[i] /= num_frames[i] == 0 ? 1 : num_frames[i];
}
comp_bit_rate = (unsigned int)
((((double) stream_length) / ((double) fields_presented)) * 2.0
* ((double) frame_rate) + 25.0) / 50;
/* Peak bit rate in 50B/sec units... */
peak_bit_rate = ((max_bits_persec / 8) / 50);
mjpeg_info ("VIDEO_STATISTICS: %02x", stream_id);
mjpeg_info ("Video Stream length: %11llu bytes", stream_length / 8);
mjpeg_info ("Sequence headers: %8u", num_sequence);
mjpeg_info ("Sequence ends : %8u", num_seq_end);
mjpeg_info ("No. Pictures : %8u", num_pictures);
mjpeg_info ("No. Groups : %8u", num_groups);
mjpeg_info ("No. I Frames : %8u avg. size%6u bytes", num_frames[0], avg_frames[0]);
mjpeg_info ("No. P Frames : %8u avg. size%6u bytes", num_frames[1], avg_frames[1]);
mjpeg_info ("No. B Frames : %8u avg. size%6u bytes", num_frames[2], avg_frames[2]);
mjpeg_info ("No. D Frames : %8u avg. size%6u bytes", num_frames[3], avg_frames[3]);
mjpeg_info ("Average bit-rate : %8u bits/sec", comp_bit_rate * 400);
mjpeg_info ("Peak bit-rate : %8u bits/sec", peak_bit_rate * 400);
}
/*************************************************************************
OutputSeqHdrInfo
Display sequence header parameters
*************************************************************************/
void
VideoStream::OutputSeqhdrInfo ()
{
const char *str;
mjpeg_info ("VIDEO STREAM: %02x", stream_id);
mjpeg_info ("Frame width : %u", horizontal_size);
mjpeg_info ("Frame height : %u", vertical_size);
if (aspect_ratio <= mpeg_num_aspect_ratios[opt_mpeg - 1])
str = mpeg_aspect_code_definition (opt_mpeg, aspect_ratio);
else
str = "forbidden";
mjpeg_info ("Aspect ratio : %s", str);
if (picture_rate == 0)
mjpeg_info ("Picture rate : forbidden");
else if (picture_rate <= mpeg_num_framerates)
mjpeg_info ("Picture rate : %2.3f frames/sec",
Y4M_RATIO_DBL (mpeg_framerate (picture_rate)));
else
mjpeg_info ("Picture rate : %x reserved", picture_rate);
if (bit_rate == 0x3ffff) {
bit_rate = 0;
mjpeg_info ("Bit rate : variable");
} else if (bit_rate == 0)
mjpeg_info ("Bit rate : forbidden");
else
mjpeg_info ("Bit rate : %u bits/sec", bit_rate * 400);
mjpeg_info ("Vbv buffer size : %u bytes", vbv_buffer_size * 2048);
mjpeg_info ("CSPF : %u", CSPF);
}
//
// Compute PTS DTS of current AU in the video sequence being
// scanned. This is is the PTS/DTS calculation for normal video only.
// It is virtual and over-ridden for non-standard streams (Stills
// etc!).
//
void
VideoStream::NextDTSPTS (clockticks & DTS, clockticks & PTS)
{
if (pict_struct != PIC_FRAME) {
DTS = static_cast < clockticks > (fields_presented * (double) (CLOCKS / 2) / frame_rate);
int dts_fields = temporal_reference * 2 + group_start_field + 1;
if (temporal_reference == prev_temp_ref)
dts_fields += 1;
PTS = static_cast < clockticks > (dts_fields * (double) (CLOCKS / 2) / frame_rate);
access_unit.porder = temporal_reference + group_start_pic;
fields_presented += 1;
} else if (pulldown_32) {
int frames2field;
int frames3field;
DTS = static_cast < clockticks > (fields_presented * (double) (CLOCKS / 2) / frame_rate);
if (repeat_first_field) {
frames2field = (temporal_reference + 1) / 2;
frames3field = temporal_reference / 2;
fields_presented += 3;
} else {
frames2field = (temporal_reference) / 2;
frames3field = (temporal_reference + 1) / 2;
fields_presented += 2;
}
PTS = static_cast < clockticks >
((frames2field * 2 + frames3field * 3 + group_start_field +
1) * (double) (CLOCKS / 2) / frame_rate);
access_unit.porder = temporal_reference + group_start_pic;
} else {
DTS = static_cast < clockticks > (decoding_order * (double) CLOCKS / frame_rate);
PTS = static_cast < clockticks >
((temporal_reference + group_start_pic + 1) * (double) CLOCKS / frame_rate);
fields_presented += 2;
}
}
/*
* Local variables:
* c-file-style: "stroustrup"
* tab-width: 4
* indent-tabs-mode: nil
* End:
*/