kopia lustrzana https://github.com/F5OEO/tstools
64 wiersze
2.3 KiB
C
64 wiersze
2.3 KiB
C
/*
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* Definitions for working with H.222 Transport Stream packets
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is the MPEG TS, PS and ES tools.
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*
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* The Initial Developer of the Original Code is Amino Communications Ltd.
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* Portions created by the Initial Developer are Copyright (C) 2008
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Amino Communications Ltd, Swavesey, Cambridge UK
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*
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* ***** END LICENSE BLOCK *****
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*/
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#ifndef _ts_defns
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#define _ts_defns
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// Transport Stream packets are always the same size
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#define TS_PACKET_SIZE 188
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// When we are putting data into a TS packet, we need the first four
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// bytes for heading information, which means that we will have at most
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// 184 bytes for our payload
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#define MAX_TS_PAYLOAD_SIZE (TS_PACKET_SIZE-4)
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// ------------------------------------------------------------
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// The number of TS packets to read ahead
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#define TS_READ_AHEAD_COUNT 1024 // aim for multiple of block boundary -- used to be 50
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// Thus the number of bytes to read ahead
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#define TS_READ_AHEAD_BYTES TS_READ_AHEAD_COUNT*TS_PACKET_SIZE
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// A read-ahead buffer for reading TS packets.
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//
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// Note that `posn` always gives the file position of the *next* TS packet to
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// be read from the file (so after reading a TS packet with
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// `read_next_TS_packet`, the position of said packet is `posn`-TS_PACKET_SIZE)
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struct _ts_reader
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{
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int file; // the file to read from
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offset_t posn; // the position of the next-to-be-read TS packet
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byte read_ahead[TS_READ_AHEAD_COUNT*TS_PACKET_SIZE];
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byte *read_ahead_ptr; // location of next packet in said array
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byte *read_ahead_end; // pointer just after the end of `read_ahead`
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};
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typedef struct _ts_reader *TS_reader_p;
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#define SIZEOF_TS_READER sizeof(struct _ts_reader)
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#endif // _ts_defns
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