adts_fns.h

/*
 * Support for ISO/IEC 14496-3:2001(E) AAC ADTS audio streams.
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the MPEG TS, PS and ES tools.
 *
 * The Initial Developer of the Original Code is Amino Communications Ltd.
 * Portions created by the Initial Developer are Copyright (C) 2008
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Amino Communications Ltd, Swavesey, Cambridge UK
 *
 * ***** END LICENSE BLOCK *****
 */

#ifndef _adts_fns
#define _adts_fns

#include "adts_defns.h"
#include "audio_fns.h"

/* Specify this flag to indicate that there is no emphasis
 *  field in the ADTS header. Generally, MPEG-2 ADTS audio
 *  (ID=0) has no emphasis field and MPEG-4 (ID=1) has 
 *  emphasis, but some H.264/AAC streams have 
 *  MPEG-4 ADTS with no emphasis and in those cases, you'll
 *  need this flag.
 */
#define ADTS_FLAG_NO_EMPHASIS  (1<<0)

/* Specify this flag to indicate that there is always an
 * emphasis field, even if the ID says there isn't one -
 * included for symmetry with NO_EMPHASIS.
 */
#define ADTS_FLAG_FORCE_EMPHASIS (1<<1)


/*
 * Read the next ADTS frame.
 *
 * Assumes that the input stream is synchronised - i.e., it does not
 * try to cope if the next three bytes are not '1111 1111 1111'.
 *
 * - `file` is the file descriptor of the ADTS file to read from
 * - `frame` is the ADTS frame that is read
 * - `flags` indicates if we are forcing the recognition of "emphasis"
 *   fields, etc.
 *
 * Returns 0 if all goes well, EOF if end-of-file is read, and 1 if something
 * goes wrong.
 */
extern int read_next_adts_frame(int            file,
                                audio_frame_p *frame,
                                unsigned int   flags);


#endif // _adts_fns

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