ffmpeg/libavcodec/libspeexdec.c

/*
 * Copyright (C) 2008 David Conrad
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <speex/speex.h>
#include <speex/speex_header.h>
#include <speex/speex_stereo.h>
#include <speex/speex_callbacks.h>
#include "avcodec.h"
#include "libavutil/common.h"

typedef struct {
    AVFrame frame;
    SpeexBits bits;
    SpeexStereoState stereo;
    void *dec_state;
    SpeexHeader *header;
    int frame_size;
} LibSpeexContext;


static av_cold int libspeex_decode_init(AVCodecContext *avctx)
{
    LibSpeexContext *s = avctx->priv_data;
    const SpeexMode *mode;
    int spx_mode;

    if (avctx->extradata_size >= 80)
        s->header = speex_packet_to_header(avctx->extradata, avctx->extradata_size);

    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
    if (s->header) {
        avctx->channels    = s->header->nb_channels;
        s->frame_size      = s->header->frame_size;
        spx_mode           = s->header->mode;
    } else {
        switch (avctx->sample_rate) {
        case 8000:  spx_mode = 0; break;
        case 16000: spx_mode = 1; break;
        case 32000: spx_mode = 2; break;
        default:
            /* libspeex can handle any mode if initialized as ultra-wideband */
            av_log(avctx, AV_LOG_WARNING, "Invalid sample rate: %d\n"
                                          "Decoding as 32kHz ultra-wideband\n",
                                          avctx->sample_rate);
            spx_mode = 2;
        }
    }

    mode = speex_lib_get_mode(spx_mode);
    if (!mode) {
        av_log(avctx, AV_LOG_ERROR, "Unknown Speex mode %d", spx_mode);
        return AVERROR_INVALIDDATA;
    }
    avctx->sample_rate = 8000 << spx_mode;

    if (avctx->channels < 1 || avctx->channels > 2) {
        /* libspeex can handle mono or stereo if initialized as stereo */
        av_log(avctx, AV_LOG_ERROR, "Invalid channel count: %d.\n"
                                    "Decoding as stereo.\n", avctx->channels);
        avctx->channels = 2;
    }

    speex_bits_init(&s->bits);
    s->dec_state = speex_decoder_init(mode);
    if (!s->dec_state) {
        av_log(avctx, AV_LOG_ERROR, "Error initializing libspeex decoder.\n");
        return -1;
    }

    if (!s->header) {
        speex_decoder_ctl(s->dec_state, SPEEX_GET_FRAME_SIZE, &s->frame_size);
    }

    if (avctx->channels == 2) {
        SpeexCallback callback;
        callback.callback_id = SPEEX_INBAND_STEREO;
        callback.func = speex_std_stereo_request_handler;
        callback.data = &s->stereo;
        s->stereo = (SpeexStereoState)SPEEX_STEREO_STATE_INIT;
        speex_decoder_ctl(s->dec_state, SPEEX_SET_HANDLER, &callback);
    }

    avcodec_get_frame_defaults(&s->frame);
    avctx->coded_frame = &s->frame;

    return 0;
}

static int libspeex_decode_frame(AVCodecContext *avctx, void *data,
                                 int *got_frame_ptr, AVPacket *avpkt)
{
    uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    LibSpeexContext *s = avctx->priv_data;
    int16_t *output;
    int ret, consumed = 0;

    /* get output buffer */
    s->frame.nb_samples = s->frame_size;
    if ((ret = avctx->get_buffer(avctx, &s->frame)) < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return ret;
    }
    output = (int16_t *)s->frame.data[0];

    /* if there is not enough data left for the smallest possible frame,
       reset the libspeex buffer using the current packet, otherwise ignore
       the current packet and keep decoding frames from the libspeex buffer. */
    if (speex_bits_remaining(&s->bits) < 43) {
        /* check for flush packet */
        if (!buf || !buf_size) {
            *got_frame_ptr = 0;
            return buf_size;
        }
        /* set new buffer */
        speex_bits_read_from(&s->bits, buf, buf_size);
        consumed = buf_size;
    }

    /* decode a single frame */
    ret = speex_decode_int(s->dec_state, &s->bits, output);
    if (ret <= -2) {
        av_log(avctx, AV_LOG_ERROR, "Error decoding Speex frame.\n");
        return AVERROR_INVALIDDATA;
    }
    if (avctx->channels == 2)
        speex_decode_stereo_int(output, s->frame_size, &s->stereo);

    *got_frame_ptr   = 1;
    *(AVFrame *)data = s->frame;

    return consumed;
}

static av_cold int libspeex_decode_close(AVCodecContext *avctx)
{
    LibSpeexContext *s = avctx->priv_data;

    speex_header_free(s->header);
    speex_bits_destroy(&s->bits);
    speex_decoder_destroy(s->dec_state);

    return 0;
}

static av_cold void libspeex_decode_flush(AVCodecContext *avctx)
{
    LibSpeexContext *s = avctx->priv_data;
    speex_bits_reset(&s->bits);
}

AVCodec ff_libspeex_decoder = {
    .name           = "libspeex",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_SPEEX,
    .priv_data_size = sizeof(LibSpeexContext),
    .init           = libspeex_decode_init,
    .close          = libspeex_decode_close,
    .decode         = libspeex_decode_frame,
    .flush          = libspeex_decode_flush,
    .capabilities   = CODEC_CAP_SUBFRAMES | CODEC_CAP_DELAY | CODEC_CAP_DR1,
    .long_name      = NULL_IF_CONFIG_SMALL("libspeex Speex"),
};