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     int frame_size;
  33 } LibSpeexContext;
  34
  35
  36 static av_cold int libspeex_decode_init(AVCodecContext *avctx)
  37 {
  38     LibSpeexContext *s = avctx->priv_data;
  39     const SpeexMode *mode;
  40
  41     // defaults in the case of a missing header
  42     if (avctx->sample_rate <= 8000)
  43         mode = &speex_nb_mode;
  44     else if (avctx->sample_rate <= 16000)
  45         mode = &speex_wb_mode;
  46     else
  47         mode = &speex_uwb_mode;
  48
  49     if (avctx->extradata_size >= 80)
  50         s->header = speex_packet_to_header(avctx->extradata, avctx->extradata_size);
  51
  52     avctx->sample_fmt = SAMPLE_FMT_S16;
  53     if (s->header) {
  54         avctx->sample_rate = s->header->rate;
  55         avctx->channels    = s->header->nb_channels;
  56         avctx->frame_size  = s->frame_size = s->header->frame_size;
  57         if (s->header->frames_per_packet)
  58             avctx->frame_size *= s->header->frames_per_packet;
  59
  60         mode = speex_lib_get_mode(s->header->mode);
  61         if (!mode) {
  62             av_log(avctx, AV_LOG_ERROR, "Unknown Speex mode %d", s->header->mode);
  63             return -1;
  64         }
  65     } else
  66         av_log(avctx, AV_LOG_INFO, "Missing Speex header, assuming defaults.\n");
  67
  68     if (avctx->channels > 2) {
  69         av_log(avctx, AV_LOG_ERROR, "Only stereo and mono are supported.\n");
  70         return -1;
  71     }
  72
  73     speex_bits_init(&s->bits);
  74     s->dec_state = speex_decoder_init(mode);
  75     if (!s->dec_state) {
  76         av_log(avctx, AV_LOG_ERROR, "Error initializing libspeex decoder.\n");
  77         return -1;
  78     }
  79
  80     if (!s->header) {
  81         speex_decoder_ctl(s->dec_state, SPEEX_GET_FRAME_SIZE, &s->frame_size);
  82     }
  83
  84     if (avctx->channels == 2) {
  85         SpeexCallback callback;
  86         callback.callback_id = SPEEX_INBAND_STEREO;
  87         callback.func = speex_std_stereo_request_handler;
  88         callback.data = &s->stereo;
  89         s->stereo = (SpeexStereoState)SPEEX_STEREO_STATE_INIT;
  90         speex_decoder_ctl(s->dec_state, SPEEX_SET_HANDLER, &callback);
  91     }
  92     return 0;
  93 }
  94
  95 static int libspeex_decode_frame(AVCodecContext *avctx,
  96                                  void *data, int *data_size,
  97                                  AVPacket *avpkt)
  98 {
  99     const uint8_t *buf = avpkt->data;
 100     int buf_size = avpkt->size;
 101     LibSpeexContext *s = avctx->priv_data;
 102     int16_t *output = data, *end;
 103     int i, num_samples;
 104
 105     num_samples = s->frame_size * avctx->channels;
 106     end = output + *data_size / sizeof(*output);
 107
 108     speex_bits_read_from(&s->bits, buf, buf_size);
 109
 110     for (i = 0; speex_bits_remaining(&s->bits) && output + num_samples < end; i++) {
 111         int ret = speex_decode_int(s->dec_state, &s->bits, output);
 112         if (ret <= -2) {
 113             av_log(avctx, AV_LOG_ERROR, "Error decoding Speex frame.\n");
 114             return -1;
 115         } else if (ret == -1)
 116             // end of stream
 117             break;
 118
 119         if (avctx->channels == 2)
 120             speex_decode_stereo_int(output, s->frame_size, &s->stereo);
 121
 122         output += num_samples;
 123     }
 124
 125     avctx->frame_size = s->frame_size * i;
 126     *data_size = avctx->channels * avctx->frame_size * sizeof(*output);
 127     return buf_size;
 128 }
 129
 130 static av_cold int libspeex_decode_close(AVCodecContext *avctx)
 131 {
 132     LibSpeexContext *s = avctx->priv_data;
 133
 134     speex_header_free(s->header);
 135     speex_bits_destroy(&s->bits);
 136     speex_decoder_destroy(s->dec_state);
 137
 138     return 0;
 139 }
 140
 141 AVCodec libspeex_decoder = {
 142     "libspeex",
 143     CODEC_TYPE_AUDIO,
 144     CODEC_ID_SPEEX,
 145     sizeof(LibSpeexContext),
 146     libspeex_decode_init,
 147     NULL,
 148     libspeex_decode_close,
 149     libspeex_decode_frame,
 150     .long_name = NULL_IF_CONFIG_SMALL("libspeex Speex"),
 151 };