kopia lustrzana https://github.com/F5OEO/tstools
126 wiersze
3.3 KiB
C
126 wiersze
3.3 KiB
C
/*
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* Generic audio functionality
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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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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include "compat.h"
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#include "printing_fns.h"
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#include "audio_fns.h"
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#include "adts_fns.h"
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#include "l2audio_fns.h"
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#include "ac3_fns.h"
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/*
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* Build a new generic audio frame datastructure
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*
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* Returns 0 if all goes well, 1 if something goes wrong.
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*/
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extern int build_audio_frame(audio_frame_p *frame)
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{
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audio_frame_p new = malloc(SIZEOF_AUDIO_FRAME);
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if (new == NULL)
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{
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fprint_err("### Unable to allocate audio frame datastructure\n");
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return 1;
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}
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new->data = NULL;
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new->data_len = 0;
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*frame = new;
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return 0;
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}
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/*
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* Tidy up and free an audio frame datastructure when we've finished with it
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*
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* Empties the datastructure, frees it, and sets `frame` to NULL.
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*
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* If `frame` is already NULL, does nothing.
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*/
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extern void free_audio_frame(audio_frame_p *frame)
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{
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if (*frame == NULL)
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return;
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if ((*frame)->data != NULL)
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{
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free((*frame)->data);
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(*frame)->data = NULL;
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}
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(*frame)->data_len = 0;
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free(*frame);
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*frame = NULL;
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}
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/*
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* Read the next audio frame.
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*
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* Assumes that the input stream is synchronised - i.e., it does not
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* try to cope if (for MPEG2) the next three bytes are not '1111 1111 1111'.
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*
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* - `file` is the file descriptor of the audio file to read from
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* - `audio_type` indicates what type of audio - e.g., AUDIO_ADTS
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* - `frame` is the audio frame that is read
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*
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* Returns 0 if all goes well, EOF if end-of-file is read, and 1 if something
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* goes wrong.
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*/
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extern int read_next_audio_frame(int file,
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int audio_type,
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audio_frame_p *frame)
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{
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switch (audio_type)
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{
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case AUDIO_ADTS_MPEG2:
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return read_next_adts_frame(file,frame,ADTS_FLAG_NO_EMPHASIS);
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case AUDIO_ADTS_MPEG4:
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return read_next_adts_frame(file,frame,ADTS_FLAG_FORCE_EMPHASIS);
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case AUDIO_ADTS:
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return read_next_adts_frame(file,frame,0);
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case AUDIO_L2:
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return read_next_l2audio_frame(file,frame);
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case AUDIO_AC3:
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return read_next_ac3_frame(file, frame);
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default:
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fprint_err("### Unrecognised audio type %d - cannot get next audio frame\n",
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audio_type);
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return 1;
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}
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}
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// Local Variables:
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// tab-width: 8
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// indent-tabs-mode: nil
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// c-basic-offset: 2
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// End:
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// vim: set tabstop=8 shiftwidth=2 expandtab:
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