105 lines
2.6 KiB
C
105 lines
2.6 KiB
C
/*
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* Interface to libmp3lame for mp3 encoding
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* Copyright (c) 2002 Lennert Buytenhek <buytenh@gnu.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "avcodec.h"
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#include <math.h>
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#include "mpegaudio.h"
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#include <lame/lame.h>
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typedef struct Mp3AudioContext {
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lame_global_flags *gfp;
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int first_frame;
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int stereo;
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} Mp3AudioContext;
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static int MP3lame_encode_init(AVCodecContext *avctx)
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{
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Mp3AudioContext *s = avctx->priv_data;
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if (avctx->channels > 2)
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return -1;
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s->first_frame = 1;
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s->stereo = avctx->channels > 1 ? 1 : 0;
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if ((s->gfp = lame_init()) == NULL)
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goto err;
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lame_set_in_samplerate(s->gfp, avctx->sample_rate);
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lame_set_out_samplerate(s->gfp, avctx->sample_rate);
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lame_set_num_channels(s->gfp, avctx->channels);
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/* lame 3.91 dies on quality != 5 */
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lame_set_quality(s->gfp, 5);
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/* lame 3.91 doesn't work in mono */
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lame_set_mode(s->gfp, JOINT_STEREO);
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lame_set_brate(s->gfp, avctx->bit_rate/1000);
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if (lame_init_params(s->gfp) < 0)
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goto err_close;
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avctx->frame_size = MPA_FRAME_SIZE;
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avctx->key_frame = 1;
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return 0;
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err_close:
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lame_close(s->gfp);
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err:
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return -1;
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}
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int MP3lame_encode_frame(AVCodecContext *avctx,
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unsigned char *frame, int buf_size, void *data)
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{
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Mp3AudioContext *s = avctx->priv_data;
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int num;
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/* lame 3.91 dies on '1-channel interleaved' data */
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if (s->stereo) {
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num = lame_encode_buffer_interleaved(s->gfp, data,
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MPA_FRAME_SIZE, frame, buf_size);
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} else {
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num = lame_encode_buffer(s->gfp, data, data, MPA_FRAME_SIZE,
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frame, buf_size);
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}
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/* lame 3.91 outputs the first frame as garbage */
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if (s->first_frame)
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s->first_frame = num = 0;
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return num;
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}
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int MP3lame_encode_close(AVCodecContext *avctx)
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{
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Mp3AudioContext *s = avctx->priv_data;
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lame_close(s->gfp);
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return 0;
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}
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AVCodec mp3lame_encoder = {
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"mp3",
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CODEC_TYPE_AUDIO,
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CODEC_ID_MP3LAME,
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sizeof(Mp3AudioContext),
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MP3lame_encode_init,
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MP3lame_encode_frame,
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MP3lame_encode_close
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};
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