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https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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429 lines
13 KiB
C++
429 lines
13 KiB
C++
/*
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* inptstrm.c: Members of video stream class related to raw stream
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* scanning and buffering.
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*
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* Copyright (C) 2001 Andrew Stevens <andrew.stevens@philips.com>
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*
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public License
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <config.h>
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#include <math.h>
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#include <stdlib.h>
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#include "videostrm.hh"
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#include "outputstream.hh"
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static void
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marker_bit (IBitStream & bs, unsigned int what)
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{
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if (what != bs.get1bit ()) {
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mjpeg_error ("Illegal MPEG stream at offset (bits) %lld: supposed marker bit not found.",
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bs.bitcount ());
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exit (1);
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}
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}
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void
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VideoStream::ScanFirstSeqHeader ()
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{
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if (bs.getbits (32) == SEQUENCE_HEADER) {
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num_sequence++;
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horizontal_size = bs.getbits (12);
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vertical_size = bs.getbits (12);
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aspect_ratio = bs.getbits (4);
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pict_rate = bs.getbits (4);
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picture_rate = pict_rate;
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bit_rate = bs.getbits (18);
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marker_bit (bs, 1);
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vbv_buffer_size = bs.getbits (10);
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CSPF = bs.get1bit ();
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} else {
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mjpeg_error ("Invalid MPEG Video stream header.");
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exit (1);
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}
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if (pict_rate > 0 && pict_rate <= mpeg_num_framerates) {
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frame_rate = Y4M_RATIO_DBL (mpeg_framerate (pict_rate));
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} else {
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frame_rate = 25.0;
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}
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}
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void
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VideoStream::Init (const int stream_num)
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{
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mjpeg_debug ("SETTING video buffer to %d", muxinto.video_buffer_size);
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MuxStream::Init (VIDEO_STR_0 + stream_num, 1, // Buffer scale
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muxinto.video_buffer_size, 0, // Zero stuffing
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muxinto.buffers_in_video, muxinto.always_buffers_in_video);
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mjpeg_info ("Scanning for header info: Video stream %02x ", VIDEO_STR_0 + stream_num);
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InitAUbuffer ();
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ScanFirstSeqHeader ();
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/* Skip to the end of the 1st AU (*2nd* Picture start!)
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*/
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AU_hdr = SEQUENCE_HEADER;
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AU_pict_data = 0;
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AU_start = 0LL;
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OutputSeqhdrInfo ();
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}
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//
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// Set the Maximum STD buffer delay for this video stream.
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// By default we set 1 second but if we have specified a video
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// buffer that can hold more than 1.0 seconds demuxed data we
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// set the delay to the time to fill the buffer.
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//
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void
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VideoStream::SetMaxStdBufferDelay (unsigned int dmux_rate)
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{
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double max_delay = CLOCKS;
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if (static_cast < double >(BufferSize ()) / dmux_rate > 1.0)
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max_delay *= static_cast < double >(BufferSize ()) / dmux_rate;
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//
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// To enforce a maximum STD buffer residency the
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// calculation is a bit tricky as when we decide to mux we may
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// (but not always) have some of the *previous* picture left to
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// mux in which case it is the timestamp of the next picture that counts.
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// For simplicity we simply reduce the limit by 1.5 frame intervals
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// and use the timestamp for the current picture.
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//
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if (frame_rate > 10.0)
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max_STD_buffer_delay = static_cast < clockticks > (max_delay * (frame_rate - 1.5) / frame_rate);
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else
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max_STD_buffer_delay = static_cast < clockticks > (10.0 * max_delay / frame_rate);
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}
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//
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// Return whether AU buffer needs refilling. There are two cases:
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// 1. We have less than our look-ahead "FRAME_CHUNK" buffer AU's
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// buffered 2. AU's are very small and we could have less than 1
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// sector's worth of data buffered.
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//
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bool
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VideoStream::AUBufferNeedsRefill ()
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{
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return
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!eoscan
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&& (aunits.current () + FRAME_CHUNK > last_buffered_AU
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|| bs.buffered_bytes () < muxinto.sector_size);
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}
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//
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// Refill the AU unit buffer setting AU PTS DTS from the scanned
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// header information...
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//
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void
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VideoStream::FillAUbuffer (unsigned int frames_to_buffer)
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{
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if (eoscan)
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return;
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last_buffered_AU += frames_to_buffer;
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mjpeg_debug ("Scanning %d video frames to frame %d", frames_to_buffer, last_buffered_AU);
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// We set a limit of 2M to seek before we give up.
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// This is intentionally very high because some heavily
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// padded still frames may have a loooong gap before
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// a following sequence end marker.
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while (!bs.eos () &&
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bs.seek_sync (SYNCWORD_START, 24, 2 * 1024 * 1024) &&
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decoding_order < last_buffered_AU)
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{
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syncword = (SYNCWORD_START << 8) + bs.getbits (8);
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if (AU_pict_data) {
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/* Handle the header *ending* an AU...
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If we have the AU picture data an AU and have now
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reached a header marking the end of an AU fill in the
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the AU length and append it to the list of AU's and
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start a new AU. I.e. sequence and gop headers count as
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part of the AU of the corresponding picture
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*/
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stream_length = bs.bitcount () - 32LL;
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switch (syncword) {
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case SEQUENCE_HEADER:
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case GROUP_START:
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case PICTURE_START:
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access_unit.start = AU_start;
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access_unit.length = (int) (stream_length - AU_start) >> 3;
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access_unit.end_seq = 0;
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avg_frames[access_unit.type - 1] += access_unit.length;
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aunits.append (access_unit);
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mjpeg_debug ("Found AU %d: DTS=%d", access_unit.dorder, (int) access_unit.DTS / 300);
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AU_hdr = syncword;
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AU_start = stream_length;
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AU_pict_data = 0;
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break;
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case SEQUENCE_END:
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access_unit.length = ((stream_length - AU_start) >> 3) + 4;
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access_unit.end_seq = 1;
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aunits.append (access_unit);
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mjpeg_info ("Scanned to end AU %d", access_unit.dorder);
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avg_frames[access_unit.type - 1] += access_unit.length;
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/* Do we have a sequence split in the video stream? */
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if (!bs.eos () && bs.getbits (32) == SEQUENCE_HEADER) {
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stream_length = bs.bitcount () - 32LL;
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AU_start = stream_length;
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syncword = AU_hdr = SEQUENCE_HEADER;
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AU_pict_data = 0;
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if (opt_multifile_segment)
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mjpeg_warn
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("Sequence end marker found in video stream but single-segment splitting specified!");
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} else {
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if (!bs.eos () && !opt_multifile_segment)
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mjpeg_warn ("No seq. header starting new sequence after seq. end!");
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}
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num_seq_end++;
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break;
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}
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}
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/* Handle the headers starting an AU... */
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switch (syncword) {
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case SEQUENCE_HEADER:
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/* TODO: Really we should update the info here so we can handle
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streams where parameters change on-the-fly... */
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num_sequence++;
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break;
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case GROUP_START:
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num_groups++;
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group_order = 0;
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break;
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case PICTURE_START:
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/* We have reached AU's picture data... */
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AU_pict_data = 1;
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prev_temp_ref = temporal_reference;
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temporal_reference = bs.getbits (10);
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access_unit.type = bs.getbits (3);
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/* Now scan forward a little for an MPEG-2 picture coding extension
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so we can get pulldown info (if present) */
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if (bs.seek_sync (EXT_START_CODE, 32, 64) && bs.getbits (4) == CODING_EXT_ID) {
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/* Skip: 4 F-codes (4)... */
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(void) bs.getbits (16);
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/* Skip: DC Precision(2) */
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(void) bs.getbits (2);
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pict_struct = bs.getbits (2);
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/* Skip: topfirst (1) frame pred dct (1),
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concealment_mv(1), q_scale_type (1), */
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(void) bs.getbits (4);
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/* Skip: intra_vlc_format(1), alternate_scan (1) */
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(void) bs.getbits (2);
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repeat_first_field = bs.getbits (1);
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pulldown_32 |= repeat_first_field;
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} else {
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repeat_first_field = 0;
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pict_struct = PIC_FRAME;
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}
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if (access_unit.type == IFRAME) {
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unsigned int bits_persec =
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(unsigned int) (((double) (stream_length - prev_offset)) *
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2 * frame_rate / ((double) (2 + fields_presented - group_start_field)));
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if (bits_persec > max_bits_persec) {
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max_bits_persec = bits_persec;
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}
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prev_offset = stream_length;
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group_start_pic = decoding_order;
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group_start_field = fields_presented;
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}
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NextDTSPTS (access_unit.DTS, access_unit.PTS);
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access_unit.dorder = decoding_order;
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access_unit.porder = temporal_reference + group_start_pic;
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access_unit.seq_header = (AU_hdr == SEQUENCE_HEADER);
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decoding_order++;
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group_order++;
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if ((access_unit.type > 0) && (access_unit.type < 5)) {
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num_frames[access_unit.type - 1]++;
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}
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if (decoding_order >= old_frames + 1000) {
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mjpeg_debug ("Got %d picture headers.", decoding_order);
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old_frames = decoding_order;
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}
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break;
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}
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}
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last_buffered_AU = decoding_order;
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num_pictures = decoding_order;
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eoscan = bs.eos ();
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}
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void
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VideoStream::Close ()
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{
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bs.close ();
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stream_length = (unsigned int) (AU_start / 8);
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for (int i = 0; i < 4; i++) {
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avg_frames[i] /= num_frames[i] == 0 ? 1 : num_frames[i];
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}
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comp_bit_rate = (unsigned int)
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((((double) stream_length) / ((double) fields_presented)) * 2.0
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* ((double) frame_rate) + 25.0) / 50;
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/* Peak bit rate in 50B/sec units... */
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peak_bit_rate = ((max_bits_persec / 8) / 50);
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mjpeg_info ("VIDEO_STATISTICS: %02x", stream_id);
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mjpeg_info ("Video Stream length: %11llu bytes", stream_length / 8);
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mjpeg_info ("Sequence headers: %8u", num_sequence);
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mjpeg_info ("Sequence ends : %8u", num_seq_end);
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mjpeg_info ("No. Pictures : %8u", num_pictures);
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mjpeg_info ("No. Groups : %8u", num_groups);
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mjpeg_info ("No. I Frames : %8u avg. size%6u bytes", num_frames[0], avg_frames[0]);
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mjpeg_info ("No. P Frames : %8u avg. size%6u bytes", num_frames[1], avg_frames[1]);
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mjpeg_info ("No. B Frames : %8u avg. size%6u bytes", num_frames[2], avg_frames[2]);
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mjpeg_info ("No. D Frames : %8u avg. size%6u bytes", num_frames[3], avg_frames[3]);
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mjpeg_info ("Average bit-rate : %8u bits/sec", comp_bit_rate * 400);
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mjpeg_info ("Peak bit-rate : %8u bits/sec", peak_bit_rate * 400);
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}
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/*************************************************************************
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OutputSeqHdrInfo
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Display sequence header parameters
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*************************************************************************/
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void
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VideoStream::OutputSeqhdrInfo ()
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{
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const char *str;
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mjpeg_info ("VIDEO STREAM: %02x", stream_id);
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mjpeg_info ("Frame width : %u", horizontal_size);
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mjpeg_info ("Frame height : %u", vertical_size);
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if (aspect_ratio <= mpeg_num_aspect_ratios[opt_mpeg - 1])
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str = mpeg_aspect_code_definition (opt_mpeg, aspect_ratio);
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else
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str = "forbidden";
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mjpeg_info ("Aspect ratio : %s", str);
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if (picture_rate == 0)
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mjpeg_info ("Picture rate : forbidden");
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else if (picture_rate <= mpeg_num_framerates)
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mjpeg_info ("Picture rate : %2.3f frames/sec",
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Y4M_RATIO_DBL (mpeg_framerate (picture_rate)));
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else
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mjpeg_info ("Picture rate : %x reserved", picture_rate);
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if (bit_rate == 0x3ffff) {
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bit_rate = 0;
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mjpeg_info ("Bit rate : variable");
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} else if (bit_rate == 0)
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mjpeg_info ("Bit rate : forbidden");
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else
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mjpeg_info ("Bit rate : %u bits/sec", bit_rate * 400);
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mjpeg_info ("Vbv buffer size : %u bytes", vbv_buffer_size * 2048);
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mjpeg_info ("CSPF : %u", CSPF);
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}
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//
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// Compute PTS DTS of current AU in the video sequence being
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// scanned. This is is the PTS/DTS calculation for normal video only.
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// It is virtual and over-ridden for non-standard streams (Stills
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// etc!).
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//
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void
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VideoStream::NextDTSPTS (clockticks & DTS, clockticks & PTS)
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{
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if (pict_struct != PIC_FRAME) {
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DTS = static_cast < clockticks > (fields_presented * (double) (CLOCKS / 2) / frame_rate);
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int dts_fields = temporal_reference * 2 + group_start_field + 1;
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if (temporal_reference == prev_temp_ref)
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dts_fields += 1;
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PTS = static_cast < clockticks > (dts_fields * (double) (CLOCKS / 2) / frame_rate);
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access_unit.porder = temporal_reference + group_start_pic;
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fields_presented += 1;
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} else if (pulldown_32) {
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int frames2field;
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int frames3field;
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DTS = static_cast < clockticks > (fields_presented * (double) (CLOCKS / 2) / frame_rate);
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if (repeat_first_field) {
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frames2field = (temporal_reference + 1) / 2;
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frames3field = temporal_reference / 2;
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fields_presented += 3;
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} else {
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frames2field = (temporal_reference) / 2;
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frames3field = (temporal_reference + 1) / 2;
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fields_presented += 2;
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}
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PTS = static_cast < clockticks >
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((frames2field * 2 + frames3field * 3 + group_start_field +
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1) * (double) (CLOCKS / 2) / frame_rate);
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access_unit.porder = temporal_reference + group_start_pic;
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} else {
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DTS = static_cast < clockticks > (decoding_order * (double) CLOCKS / frame_rate);
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PTS = static_cast < clockticks >
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((temporal_reference + group_start_pic + 1) * (double) CLOCKS / frame_rate);
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fields_presented += 2;
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}
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}
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/*
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* Local variables:
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* c-file-style: "stroustrup"
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* tab-width: 4
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* indent-tabs-mode: nil
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* End:
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*/
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