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libavcodec/libspeexdec.c

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00001 /*
00002  * Copyright (C) 2008 David Conrad
00003  *
00004  * This file is part of FFmpeg.
00005  *
00006  * FFmpeg is free software; you can redistribute it and/or
00007  * modify it under the terms of the GNU Lesser General Public
00008  * License as published by the Free Software Foundation; either
00009  * version 2.1 of the License, or (at your option) any later version.
00010  *
00011  * FFmpeg is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014  * Lesser General Public License for more details.
00015  *
00016  * You should have received a copy of the GNU Lesser General Public
00017  * License along with FFmpeg; if not, write to the Free Software
00018  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00019  */
00020 
00021 #include "avcodec.h"
00022 #include <speex/speex.h>
00023 #include <speex/speex_header.h>
00024 #include <speex/speex_stereo.h>
00025 #include <speex/speex_callbacks.h>
00026 
00027 typedef struct {
00028     SpeexBits bits;
00029     SpeexStereoState stereo;
00030     void *dec_state;
00031     SpeexHeader *header;
00032     int frame_size;
00033 } LibSpeexContext;
00034 
00035 
00036 static av_cold int libspeex_decode_init(AVCodecContext *avctx)
00037 {
00038     LibSpeexContext *s = avctx->priv_data;
00039     const SpeexMode *mode;
00040 
00041     // defaults in the case of a missing header
00042     if (avctx->sample_rate <= 8000)
00043         mode = &speex_nb_mode;
00044     else if (avctx->sample_rate <= 16000)
00045         mode = &speex_wb_mode;
00046     else
00047         mode = &speex_uwb_mode;
00048 
00049     if (avctx->extradata_size >= 80)
00050         s->header = speex_packet_to_header(avctx->extradata, avctx->extradata_size);
00051 
00052     avctx->sample_fmt = SAMPLE_FMT_S16;
00053     if (s->header) {
00054         avctx->sample_rate = s->header->rate;
00055         avctx->channels    = s->header->nb_channels;
00056         avctx->frame_size  = s->frame_size = s->header->frame_size;
00057         if (s->header->frames_per_packet)
00058             avctx->frame_size *= s->header->frames_per_packet;
00059 
00060         mode = speex_lib_get_mode(s->header->mode);
00061         if (!mode) {
00062             av_log(avctx, AV_LOG_ERROR, "Unknown Speex mode %d", s->header->mode);
00063             return -1;
00064         }
00065     } else
00066         av_log(avctx, AV_LOG_INFO, "Missing Speex header, assuming defaults.\n");
00067 
00068     if (avctx->channels > 2) {
00069         av_log(avctx, AV_LOG_ERROR, "Only stereo and mono are supported.\n");
00070         return -1;
00071     }
00072 
00073     speex_bits_init(&s->bits);
00074     s->dec_state = speex_decoder_init(mode);
00075     if (!s->dec_state) {
00076         av_log(avctx, AV_LOG_ERROR, "Error initializing libspeex decoder.\n");
00077         return -1;
00078     }
00079 
00080     if (!s->header) {
00081         speex_decoder_ctl(s->dec_state, SPEEX_GET_FRAME_SIZE, &s->frame_size);
00082     }
00083 
00084     if (avctx->channels == 2) {
00085         SpeexCallback callback;
00086         callback.callback_id = SPEEX_INBAND_STEREO;
00087         callback.func = speex_std_stereo_request_handler;
00088         callback.data = &s->stereo;
00089         s->stereo = (SpeexStereoState)SPEEX_STEREO_STATE_INIT;
00090         speex_decoder_ctl(s->dec_state, SPEEX_SET_HANDLER, &callback);
00091     }
00092     return 0;
00093 }
00094 
00095 static int libspeex_decode_frame(AVCodecContext *avctx,
00096                                  void *data, int *data_size,
00097                                  AVPacket *avpkt)
00098 {
00099     const uint8_t *buf = avpkt->data;
00100     int buf_size = avpkt->size;
00101     LibSpeexContext *s = avctx->priv_data;
00102     int16_t *output = data, *end;
00103     int i, num_samples;
00104 
00105     num_samples = s->frame_size * avctx->channels;
00106     end = output + *data_size / sizeof(*output);
00107 
00108     speex_bits_read_from(&s->bits, buf, buf_size);
00109 
00110     for (i = 0; speex_bits_remaining(&s->bits) && output + num_samples < end; i++) {
00111         int ret = speex_decode_int(s->dec_state, &s->bits, output);
00112         if (ret <= -2) {
00113             av_log(avctx, AV_LOG_ERROR, "Error decoding Speex frame.\n");
00114             return -1;
00115         } else if (ret == -1)
00116             // end of stream
00117             break;
00118 
00119         if (avctx->channels == 2)
00120             speex_decode_stereo_int(output, s->frame_size, &s->stereo);
00121 
00122         output += num_samples;
00123     }
00124 
00125     avctx->frame_size = s->frame_size * i;
00126     *data_size = avctx->channels * avctx->frame_size * sizeof(*output);
00127     return buf_size;
00128 }
00129 
00130 static av_cold int libspeex_decode_close(AVCodecContext *avctx)
00131 {
00132     LibSpeexContext *s = avctx->priv_data;
00133 
00134     speex_header_free(s->header);
00135     speex_bits_destroy(&s->bits);
00136     speex_decoder_destroy(s->dec_state);
00137 
00138     return 0;
00139 }
00140 
00141 AVCodec libspeex_decoder = {
00142     "libspeex",
00143     AVMEDIA_TYPE_AUDIO,
00144     CODEC_ID_SPEEX,
00145     sizeof(LibSpeexContext),
00146     libspeex_decode_init,
00147     NULL,
00148     libspeex_decode_close,
00149     libspeex_decode_frame,
00150     .long_name = NULL_IF_CONFIG_SMALL("libspeex Speex"),
00151 };

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