F5OEO-tstools/audio.c

122 wiersze
3.2 KiB
C
Czysty Wina Historia

This file contains invisible Unicode characters!

This file contains invisible Unicode characters that may be processed differently from what appears below. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to reveal hidden characters.

/*
* 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 "audio_fns.h"
#include "adts_fns.h"
#include "l2audio_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)
{
fprintf(stderr,"### 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);
default:
fprintf(stderr,"### 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: