hvirtual/quicktime/libavcodec/mp3lameaudio.c

   1 /*
   2  * Interface to libmp3lame for mp3 encoding
   3  * Copyright (c) 2002 Lennert Buytenhek <buytenh@gnu.org>
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include "avcodec.h"
  21 #include "mpegaudio.h"
  22 #include <lame/lame.h>
  23
  24 typedef struct Mp3AudioContext {
  25         lame_global_flags *gfp;
  26         int stereo;
  27 } Mp3AudioContext;
  28
  29
  30 static int MP3lame_encode_init(AVCodecContext *avctx)
  31 {
  32         Mp3AudioContext *s = avctx->priv_data;
  33
  34         if (avctx->channels > 2)
  35                 return -1;
  36
  37         s->stereo = avctx->channels > 1 ? 1 : 0;
  38
  39         if ((s->gfp = lame_init()) == NULL)
  40                 goto err;
  41         lame_set_in_samplerate(s->gfp, avctx->sample_rate);
  42         lame_set_out_samplerate(s->gfp, avctx->sample_rate);
  43         lame_set_num_channels(s->gfp, avctx->channels);
  44         /* lame 3.91 dies on quality != 5 */
  45         lame_set_quality(s->gfp, 5);
  46         /* lame 3.91 doesn't work in mono */
  47         lame_set_mode(s->gfp, JOINT_STEREO);
  48         lame_set_brate(s->gfp, avctx->bit_rate/1000);
  49         if (lame_init_params(s->gfp) < 0)
  50                 goto err_close;
  51
  52         avctx->frame_size = MPA_FRAME_SIZE;
  53
  54         avctx->coded_frame= avcodec_alloc_frame();
  55         avctx->coded_frame->key_frame= 1;
  56
  57         return 0;
  58
  59 err_close:
  60         lame_close(s->gfp);
  61 err:
  62         return -1;
  63 }
  64
  65 int MP3lame_encode_frame(AVCodecContext *avctx,
  66                      unsigned char *frame, int buf_size, void *data)
  67 {
  68         Mp3AudioContext *s = avctx->priv_data;
  69         int num;
  70
  71         /* lame 3.91 dies on '1-channel interleaved' data */
  72         if (s->stereo) {
  73                 num = lame_encode_buffer_interleaved(s->gfp, data,
  74                         MPA_FRAME_SIZE, frame, buf_size);
  75         } else {
  76                 num = lame_encode_buffer(s->gfp, data, data, MPA_FRAME_SIZE,
  77                         frame, buf_size);
  78         }
  79
  80         return num;
  81 }
  82
  83 int MP3lame_encode_close(AVCodecContext *avctx)
  84 {
  85         Mp3AudioContext *s = avctx->priv_data;
  86
  87         av_freep(&avctx->coded_frame);
  88
  89         lame_close(s->gfp);
  90         return 0;
  91 }
  92
  93
  94 AVCodec mp3lame_encoder = {
  95     "mp3",
  96     CODEC_TYPE_AUDIO,
  97     CODEC_ID_MP3LAME,
  98     sizeof(Mp3AudioContext),
  99     MP3lame_encode_init,
 100     MP3lame_encode_frame,
 101     MP3lame_encode_close
 102 };