/* * inptstrm.c: Members of video stream class related to raw stream * scanning and buffering. * * Copyright (C) 2001 Andrew Stevens * * * 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 #include #include #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: */