libavcodec/libspeexdec.c

   1 /*
   2  * Copyright (C) 2008 David Conrad
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "avcodec.h"
  22 #include <speex/speex.h>
  23 #include <speex/speex_header.h>
  24 #include <speex/speex_stereo.h>
  25 #include <speex/speex_callbacks.h>
  26
  27 typedef struct {
  28     SpeexBits bits;
  29     SpeexStereoState stereo;
  30     void *dec_state;
  31     SpeexHeader *header;
  32 } LibSpeexContext;
  33
  34
  35 static av_cold int libspeex_decode_init(AVCodecContext *avctx)
  36 {
  37     LibSpeexContext *s = avctx->priv_data;
  38     const SpeexMode *mode;
  39
  40     // defaults in the case of a missing header
  41     if (avctx->sample_rate <= 8000)
  42         mode = &speex_nb_mode;
  43     else if (avctx->sample_rate <= 16000)
  44         mode = &speex_wb_mode;
  45     else
  46         mode = &speex_uwb_mode;
  47
  48     if (avctx->extradata_size >= 80)
  49         s->header = speex_packet_to_header(avctx->extradata, avctx->extradata_size);
  50
  51     avctx->sample_fmt = SAMPLE_FMT_S16;
  52     if (s->header) {
  53         avctx->sample_rate = s->header->rate;
  54         avctx->channels    = s->header->nb_channels;
  55         avctx->frame_size  = s->header->frame_size;
  56
  57         mode = speex_lib_get_mode(s->header->mode);
  58         if (!mode) {
  59             av_log(avctx, AV_LOG_ERROR, "Unknown Speex mode %d", s->header->mode);
  60             return -1;
  61         }
  62     } else
  63         av_log(avctx, AV_LOG_INFO, "Missing Speex header, assuming defaults.\n");
  64
  65     if (avctx->channels > 2) {
  66         av_log(avctx, AV_LOG_ERROR, "Only stereo and mono are supported.\n");
  67         return -1;
  68     }
  69
  70     speex_bits_init(&s->bits);
  71     s->dec_state = speex_decoder_init(mode);
  72     if (!s->dec_state) {
  73         av_log(avctx, AV_LOG_ERROR, "Error initializing libspeex decoder.\n");
  74         return -1;
  75     }
  76
  77     if (!s->header)
  78         speex_decoder_ctl(s->dec_state, SPEEX_GET_FRAME_SIZE, &avctx->frame_size);
  79
  80     if (avctx->channels == 2) {
  81         SpeexCallback callback;
  82         callback.callback_id = SPEEX_INBAND_STEREO;
  83         callback.func = speex_std_stereo_request_handler;
  84         callback.data = &s->stereo;
  85         s->stereo = (SpeexStereoState)SPEEX_STEREO_STATE_INIT;
  86         speex_decoder_ctl(s->dec_state, SPEEX_SET_HANDLER, &callback);
  87     }
  88     return 0;
  89 }
  90
  91 static int libspeex_decode_frame(AVCodecContext *avctx,
  92                                  void *data, int *data_size,
  93                                  AVPacket *avpkt)
  94 {
  95     const uint8_t *buf = avpkt->data;
  96     int buf_size = avpkt->size;
  97     LibSpeexContext *s = avctx->priv_data;
  98     int16_t *output = data, *end;
  99     int i, num_samples;
 100
 101     num_samples = avctx->frame_size * avctx->channels;
 102     end = output + *data_size/2;
 103
 104     speex_bits_read_from(&s->bits, buf, buf_size);
 105
 106     for (i = 0; speex_bits_remaining(&s->bits) && output + num_samples < end; i++) {
 107         int ret = speex_decode_int(s->dec_state, &s->bits, output);
 108         if (ret <= -2) {
 109             av_log(avctx, AV_LOG_ERROR, "Error decoding Speex frame.\n");
 110             return -1;
 111         } else if (ret == -1)
 112             // end of stream
 113             break;
 114
 115         if (avctx->channels == 2)
 116             speex_decode_stereo_int(output, avctx->frame_size, &s->stereo);
 117
 118         output += num_samples;
 119     }
 120
 121     *data_size = i * avctx->channels * avctx->frame_size * 2;
 122     return buf_size;
 123 }
 124
 125 static av_cold int libspeex_decode_close(AVCodecContext *avctx)
 126 {
 127     LibSpeexContext *s = avctx->priv_data;
 128
 129     speex_header_free(s->header);
 130     speex_bits_destroy(&s->bits);
 131     speex_decoder_destroy(s->dec_state);
 132
 133     return 0;
 134 }
 135
 136 AVCodec libspeex_decoder = {
 137     "libspeex",
 138     CODEC_TYPE_AUDIO,
 139     CODEC_ID_SPEEX,
 140     sizeof(LibSpeexContext),
 141     libspeex_decode_init,
 142     NULL,
 143     libspeex_decode_close,
 144     libspeex_decode_frame,
 145     .long_name = NULL_IF_CONFIG_SMALL("libspeex Speex"),
 146 };