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/*
* Generic audio functionality
*
* ***** 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 *****
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include "compat.h"
#include "printing_fns.h"
#include "audio_fns.h"
#include "adts_fns.h"
#include "l2audio_fns.h"
#include "ac3_fns.h"
/*
* Build a new generic audio frame datastructure
*
* Returns 0 if all goes well, 1 if something goes wrong.
*/
extern int build_audio_frame(audio_frame_p *frame)
{
audio_frame_p new = malloc(SIZEOF_AUDIO_FRAME);
if (new == NULL)
{
fprint_err("### Unable to allocate audio frame datastructure\n");
return 1;
}
new->data = NULL;
new->data_len = 0;
*frame = new;
return 0;
}
/*
* Tidy up and free an audio frame datastructure when we've finished with it
*
* Empties the datastructure, frees it, and sets `frame` to NULL.
*
* If `frame` is already NULL, does nothing.
*/
extern void free_audio_frame(audio_frame_p *frame)
{
if (*frame == NULL)
return;
if ((*frame)->data != NULL)
{
free((*frame)->data);
(*frame)->data = NULL;
}
(*frame)->data_len = 0;
free(*frame);
*frame = NULL;
}
/*
* Read the next audio frame.
*
* Assumes that the input stream is synchronised - i.e., it does not
* try to cope if (for MPEG2) the next three bytes are not '1111 1111 1111'.
*
* - `file` is the file descriptor of the audio file to read from
* - `audio_type` indicates what type of audio - e.g., AUDIO_ADTS
* - `frame` is the audio frame that is read
*
* Returns 0 if all goes well, EOF if end-of-file is read, and 1 if something
* goes wrong.
*/
extern int read_next_audio_frame(int file,
int audio_type,
audio_frame_p *frame)
{
switch (audio_type)
{
case AUDIO_ADTS_MPEG2:
return read_next_adts_frame(file,frame,ADTS_FLAG_NO_EMPHASIS);
case AUDIO_ADTS_MPEG4:
return read_next_adts_frame(file,frame,ADTS_FLAG_FORCE_EMPHASIS);
case AUDIO_ADTS:
return read_next_adts_frame(file,frame,0);
case AUDIO_L2:
return read_next_l2audio_frame(file,frame);
case AUDIO_AC3:
return read_next_ac3_frame(file, frame);
default:
fprint_err("### Unrecognised audio type %d - cannot get next audio frame\n",
audio_type);
return 1;
}
}
// Local Variables:
// tab-width: 8
// indent-tabs-mode: nil
// c-basic-offset: 2
// End:
// vim: set tabstop=8 shiftwidth=2 expandtab:
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