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276 lines
8.2 KiB
C++
276 lines
8.2 KiB
C++
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/*
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* inptstrm.c: Members of input stream classes related to muxing out into
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* the output stream.
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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 <assert.h>
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#include "fastintfns.h"
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#include "videostrm.hh"
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#include "outputstream.hh"
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VideoStream::VideoStream (IBitStream & ibs, OutputStream & into):
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ElementaryStream (ibs, into, ElementaryStream::video),
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num_sequence (0),
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num_seq_end (0),
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num_pictures (0),
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num_groups (0), dtspts_for_all_au (into.dtspts_for_all_vau), gop_control_packet (false)
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{
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prev_offset = 0;
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decoding_order = 0;
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fields_presented = 0;
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group_order = 0;
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group_start_pic = 0;
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group_start_field = 0;
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temporal_reference = 0;
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pulldown_32 = 0;
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temporal_reference = -1; // Needed to recognise 2nd field of 1st
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// frame in a field pic sequence
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last_buffered_AU = 0;
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max_bits_persec = 0;
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AU_hdr = SEQUENCE_HEADER; /* GOP or SEQ Header starting AU? */
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for (int i = 0; i < 4; ++i)
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num_frames[i] = avg_frames[i] = 0;
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FRAME_CHUNK = 6;
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this->opt_mpeg = into.opt_mpeg;
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this->opt_multifile_segment = into.opt_multifile_segment;
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}
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bool
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VideoStream::Probe (IBitStream & bs)
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{
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return bs.getbits (32) == 0x1b3;
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}
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void
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VideoStream::InitAUbuffer ()
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{
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unsigned int i;
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for (i = 0; i < aunits.BUF_SIZE; ++i)
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aunits.init (new VAunit);
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}
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/*********************************
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* Signals when video stream has completed mux run-out specified
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* in associated mux stream. Run-out is always to complete GOP's.
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*********************************/
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bool
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VideoStream::RunOutComplete ()
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{
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return (au_unsent == 0 ||
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(muxinto.running_out && au->type == IFRAME && RequiredPTS () >= muxinto.runout_PTS));
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}
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/*********************************
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* Signals if it is permissible/possible to Mux out a sector from the Stream.
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* The universal constraints that muxing should not be complete and that
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* that the reciever buffer should have sufficient it also insists that
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* the muxed data won't hang around in the receiver buffer for more than
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* one second. This is mainly for the benefit of (S)VCD and DVD applications
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* where long delays mess up random access.
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*******************************/
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bool
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VideoStream::MuxPossible (clockticks currentSCR)
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{
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return (ElementaryStream::MuxPossible (currentSCR) &&
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RequiredDTS () < currentSCR + max_STD_buffer_delay);
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}
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/*********************************
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* Work out the timestamps to be set in the header of sectors starting
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* new AU's.
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*********************************/
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uint8_t
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VideoStream::NewAUTimestamps (int AUtype)
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{
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uint8_t timestamps;
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if (AUtype == BFRAME)
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timestamps = TIMESTAMPBITS_PTS;
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else
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timestamps = TIMESTAMPBITS_PTS_DTS;
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if (muxinto.timestamp_iframe_only && AUtype != IFRAME)
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timestamps = TIMESTAMPBITS_NO;
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return timestamps;
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}
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/*********************************
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* Work out the buffer records to be set in the header of sectors
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* starting new AU's.
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*********************************/
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bool
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VideoStream::NewAUBuffers (int AUtype)
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{
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return buffers_in_header & !(muxinto.video_buffers_iframe_only && AUtype != IFRAME);
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}
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/******************************************************************
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Output_Video
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generiert Pack/Sys_Header/Packet Informationen aus dem
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Video Stream und speichert den so erhaltenen Sektor ab.
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generates Pack/Sys_Header/Packet information from the
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video stream and writes out the new sector
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******************************************************************/
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void
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VideoStream::OutputSector ()
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{
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unsigned int max_packet_payload;
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unsigned int actual_payload;
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unsigned int old_au_then_new_payload;
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clockticks DTS, PTS;
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int autype;
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max_packet_payload = 0; /* 0 = Fill sector */
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/*
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We're now in the last AU of a segment.
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So we don't want to go beyond it's end when filling
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sectors. Hence we limit packet payload size to (remaining) AU length.
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The same applies when we wish to ensure sequence headers starting
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ACCESS-POINT AU's in (S)VCD's etc are sector-aligned.
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*/
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int nextAU = NextAUType ();
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if ((muxinto.running_out && nextAU == IFRAME &&
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NextRequiredPTS () > muxinto.runout_PTS) ||
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(muxinto.sector_align_iframeAUs && nextAU == IFRAME)
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) {
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max_packet_payload = au_unsent;
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}
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/* Figure out the threshold payload size below which we can fit more
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than one AU into a packet N.b. because fitting more than one in
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imposses an overhead of additional header fields so there is a
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dead spot where we *have* to stuff the packet rather than start
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fitting in an extra AU. Slightly over-conservative in the case
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of the last packet... */
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old_au_then_new_payload = muxinto.PacketPayload (*this, buffers_in_header, true, true);
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/* CASE: Packet starts with new access unit */
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if (new_au_next_sec) {
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autype = AUType ();
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//
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// Some types of output format (e.g. DVD) require special
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// control sectors before the sector starting a new GOP
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// N.b. this implies muxinto.sector_align_iframeAUs
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//
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if (gop_control_packet && autype == IFRAME) {
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OutputGOPControlSector ();
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}
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if (dtspts_for_all_au && max_packet_payload == 0)
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max_packet_payload = au_unsent;
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PTS = RequiredPTS ();
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DTS = RequiredDTS ();
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actual_payload =
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muxinto.WritePacket (max_packet_payload,
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*this, NewAUBuffers (autype), PTS, DTS, NewAUTimestamps (autype));
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}
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/* CASE: Packet begins with old access unit, no new one */
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/* can begin in the very same packet */
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else if (au_unsent >= old_au_then_new_payload ||
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(max_packet_payload != 0 && au_unsent >= max_packet_payload)) {
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actual_payload = muxinto.WritePacket (au_unsent, *this, false, 0, 0, TIMESTAMPBITS_NO);
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}
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/* CASE: Packet begins with old access unit, a new one */
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/* could begin in the very same packet */
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else { /* if ( !new_au_next_sec &&
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(au_unsent < old_au_then_new_payload)) */
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/* Is there a new access unit ? */
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if (Lookahead () != 0) {
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autype = NextAUType ();
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if (dtspts_for_all_au && max_packet_payload == 0)
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max_packet_payload = au_unsent + Lookahead ()->length;
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PTS = NextRequiredPTS ();
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DTS = NextRequiredDTS ();
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actual_payload =
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muxinto.WritePacket (max_packet_payload,
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*this, NewAUBuffers (autype), PTS, DTS, NewAUTimestamps (autype));
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} else {
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actual_payload = muxinto.WritePacket (0, *this, false, 0, 0, TIMESTAMPBITS_NO);
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}
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}
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++nsec;
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buffers_in_header = always_buffers_in_header;
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}
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/***********************************************
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OutputControlSector - Write control sectors prefixing a GOP
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For "normal" video streams this doesn't happen and so represents
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a bug and triggers an abort.
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In DVD's these sectors carry a system header and what is
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presumably indexing and/or sub-title information in
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private_stream_2 packets. I have no idea what to put in here so we
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simply pad the sector out.
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***********************************************/
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void
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VideoStream::OutputGOPControlSector ()
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{
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abort ();
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}
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/******************************************************************
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* OutputGOPControlSector
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* DVD System headers are carried in peculiar sectors carrying 2
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* PrivateStream2 packets. We're sticking 0's in the packets
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* as we have no idea what's supposed to be in there.
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******************************************************************/
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void
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DVDVideoStream::OutputGOPControlSector ()
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{
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muxinto.OutputDVDPriv2 ();
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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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