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         if (s->header->frames_per_packet)
  57             avctx->frame_size *= s->header->frames_per_packet;
  58
  59         mode = speex_lib_get_mode(s->header->mode);
  60         if (!mode) {
  61             av_log(avctx, AV_LOG_ERROR, "Unknown Speex mode %d", s->header->mode);
  62             return -1;
  63         }
  64     } else
  65         av_log(avctx, AV_LOG_INFO, "Missing Speex header, assuming defaults.\n");
  66
  67     if (avctx->channels > 2) {
  68         av_log(avctx, AV_LOG_ERROR, "Only stereo and mono are supported.\n");
  69         return -1;
  70     }
  71
  72     speex_bits_init(&s->bits);
  73     s->dec_state = speex_decoder_init(mode);
  74     if (!s->dec_state) {
  75         av_log(avctx, AV_LOG_ERROR, "Error initializing libspeex decoder.\n");
  76         return -1;
  77     }
  78
  79     if (!s->header)
  80         speex_decoder_ctl(s->dec_state, SPEEX_GET_FRAME_SIZE, &avctx->frame_size);
  81
  82     if (avctx->channels == 2) {
  83         SpeexCallback callback;
  84         callback.callback_id = SPEEX_INBAND_STEREO;
  85         callback.func = speex_std_stereo_request_handler;
  86         callback.data = &s->stereo;
  87         s->stereo = (SpeexStereoState)SPEEX_STEREO_STATE_INIT;
  88         speex_decoder_ctl(s->dec_state, SPEEX_SET_HANDLER, &callback);
  89     }
  90     return 0;
  91 }
  92
  93 static int libspeex_decode_frame(AVCodecContext *avctx,
  94                                  void *data, int *data_size,
  95                                  AVPacket *avpkt)
  96 {
  97     const uint8_t *buf = avpkt->data;
  98     int buf_size = avpkt->size;
  99     LibSpeexContext *s = avctx->priv_data;
 100     int16_t *output = data, *end;
 101     int i, num_samples;
 102
 103     num_samples = s->header->frame_size * avctx->channels;
 104     end = output + *data_size / sizeof(*output);
 105
 106     speex_bits_read_from(&s->bits, buf, buf_size);
 107
 108     for (i = 0; speex_bits_remaining(&s->bits) && output + num_samples < end; i++) {
 109         int ret = speex_decode_int(s->dec_state, &s->bits, output);
 110         if (ret <= -2) {
 111             av_log(avctx, AV_LOG_ERROR, "Error decoding Speex frame.\n");
 112             return -1;
 113         } else if (ret == -1)
 114             // end of stream
 115             break;
 116
 117         if (avctx->channels == 2)
 118             speex_decode_stereo_int(output, s->header->frame_size, &s->stereo);
 119
 120         output += num_samples;
 121     }
 122
 123     avctx->frame_size = s->header->frame_size * i;
 124     *data_size = avctx->channels * avctx->frame_size * sizeof(*output);
 125     return buf_size;
 126 }
 127
 128 static av_cold int libspeex_decode_close(AVCodecContext *avctx)
 129 {
 130     LibSpeexContext *s = avctx->priv_data;
 131
 132     speex_header_free(s->header);
 133     speex_bits_destroy(&s->bits);
 134     speex_decoder_destroy(s->dec_state);
 135
 136     return 0;
 137 }
 138
 139 AVCodec libspeex_decoder = {
 140     "libspeex",
 141     CODEC_TYPE_AUDIO,
 142     CODEC_ID_SPEEX,
 143     sizeof(LibSpeexContext),
 144     libspeex_decode_init,
 145     NULL,
 146     libspeex_decode_close,
 147     libspeex_decode_frame,
 148     .long_name = NULL_IF_CONFIG_SMALL("libspeex Speex"),
 149 };