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/*

 * Copyright (C) 2009 Justin Ruggles

 * Copyright (c) 2009 Xuggle Incorporated

 *

 * 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

 */

/**

 * @file

 * libspeex Speex audio encoder

 *

 * Usage Guide

 * This explains the values that need to be set prior to initialization in

 * order to control various encoding parameters.

 *

 * Channels

 *     Speex only supports mono or stereo, so avctx->channels must be set to

 *     1 or 2.

 *

 * Sample Rate / Encoding Mode

 *     Speex has 3 modes, each of which uses a specific sample rate.

 *         narrowband     :  8 kHz

 *         wideband       : 16 kHz

 *         ultra-wideband : 32 kHz

 *     avctx->sample_rate must be set to one of these 3 values.  This will be

 *     used to set the encoding mode.

 *

 * Rate Control

 *     VBR mode is turned on by setting CODEC_FLAG_QSCALE in avctx->flags.

 *     avctx->global_quality is used to set the encoding quality.

 *     For CBR mode, avctx->bit_rate can be used to set the constant bitrate.

 *     Alternatively, the 'cbr_quality' option can be set from 0 to 10 to set

 *     a constant bitrate based on quality.

 *     For ABR mode, set avctx->bit_rate and set the 'abr' option to 1.

 *     Approx. Bitrate Range:

 *         narrowband     : 2400 - 25600 bps

 *         wideband       : 4000 - 43200 bps

 *         ultra-wideband : 4400 - 45200 bps

 *

 * Complexity

 *     Encoding complexity is controlled by setting avctx->compression_level.

 *     The valid range is 0 to 10.  A higher setting gives generally better

 *     quality at the expense of encoding speed.  This does not affect the

 *     bit rate.

 *

 * Frames-per-Packet

 *     The encoder defaults to using 1 frame-per-packet.  However, it is

 *     sometimes desirable to use multiple frames-per-packet to reduce the

 *     amount of container overhead.  This can be done by setting the

 *     'frames_per_packet' option to a value 1 to 8.

 *

 *

 * Optional features

 * Speex encoder supports several optional features, which can be useful

 * for some conditions.

 *

 * Voice Activity Detection

 *     When enabled, voice activity detection detects whether the audio

 *     being encoded is speech or silence/background noise. VAD is always

 *     implicitly activated when encoding in VBR, so the option is only useful

 *     in non-VBR operation. In this case, Speex detects non-speech periods and

 *     encodes them with just enough bits to reproduce the background noise.

 *

 * Discontinuous Transmission (DTX)

 *     DTX is an addition to VAD/VBR operation, that allows to stop transmitting

 *     completely when the background noise is stationary.

 *     In file-based operation only 5 bits are used for such frames.

 */

#include 

#include 

#include 

#include "libavutil/channel_layout.h"

#include "libavutil/common.h"

#include "libavutil/opt.h"

#include "avcodec.h"

#include "internal.h"

#include "audio_frame_queue.h"

/* TODO: Think about converting abr, vad, dtx and such flags to a bit field */

typedef struct {

    AVClass *class;             ///< AVClass for private options

    SpeexBits bits;             ///< libspeex bitwriter context

    SpeexHeader header;         ///< libspeex header struct

    void *enc_state;            ///< libspeex encoder state

    int frames_per_packet;      ///< number of frames to encode in each packet

    float vbr_quality;          ///< VBR quality 0.0 to 10.0

    int cbr_quality;            ///< CBR quality 0 to 10

    int abr;                    ///< flag to enable ABR

    int vad;                    ///< flag to enable VAD

    int dtx;                    ///< flag to enable DTX

    int pkt_frame_count;        ///< frame count for the current packet

    AudioFrameQueue afq;        ///< frame queue

} LibSpeexEncContext;

static av_cold void print_enc_params(AVCodecContext *avctx,

                                     LibSpeexEncContext *s)

{

    const char *mode_str = "unknown";

    av_log(avctx, AV_LOG_DEBUG, "channels: %d\n", avctx->channels);

    switch (s->header.mode) {

    case SPEEX_MODEID_NB:  mode_str = "narrowband";     break;

    case SPEEX_MODEID_WB:  mode_str = "wideband";       break;

    case SPEEX_MODEID_UWB: mode_str = "ultra-wideband"; break;

    }

    av_log(avctx, AV_LOG_DEBUG, "mode: %s\n", mode_str);

    if (s->header.vbr) {

        av_log(avctx, AV_LOG_DEBUG, "rate control: VBR\n");

        av_log(avctx, AV_LOG_DEBUG, "  quality: %f\n", s->vbr_quality);

    } else if (s->abr) {

        av_log(avctx, AV_LOG_DEBUG, "rate control: ABR\n");

        av_log(avctx, AV_LOG_DEBUG, "  bitrate: %d bps\n", avctx->bit_rate);

    } else {

        av_log(avctx, AV_LOG_DEBUG, "rate control: CBR\n");

        av_log(avctx, AV_LOG_DEBUG, "  bitrate: %d bps\n", avctx->bit_rate);

    }

    av_log(avctx, AV_LOG_DEBUG, "complexity: %d\n",

           avctx->compression_level);

    av_log(avctx, AV_LOG_DEBUG, "frame size: %d samples\n",

           avctx->frame_size);

    av_log(avctx, AV_LOG_DEBUG, "frames per packet: %d\n",

           s->frames_per_packet);

    av_log(avctx, AV_LOG_DEBUG, "packet size: %d\n",

           avctx->frame_size * s->frames_per_packet);

    av_log(avctx, AV_LOG_DEBUG, "voice activity detection: %d\n", s->vad);

    av_log(avctx, AV_LOG_DEBUG, "discontinuous transmission: %d\n", s->dtx);

}

static av_cold int encode_init(AVCodecContext *avctx)

{

    LibSpeexEncContext *s = avctx->priv_data;

    const SpeexMode *mode;

    uint8_t *header_data;

    int header_size;

    int32_t complexity;

    /* channels */

    if (avctx->channels < 1 || avctx->channels > 2) {

        av_log(avctx, AV_LOG_ERROR, "Invalid channels (%d). Only stereo and "

               "mono are supported\n", avctx->channels);

        return AVERROR(EINVAL);

    }

    /* sample rate and encoding mode */

    switch (avctx->sample_rate) {

    case  8000: mode = &speex_nb_mode;  break;

    case 16000: mode = &speex_wb_mode;  break;

    case 32000: mode = &speex_uwb_mode; break;

    default:

        av_log(avctx, AV_LOG_ERROR, "Sample rate of %d Hz is not supported. "

               "Resample to 8, 16, or 32 kHz.\n", avctx->sample_rate);

        return AVERROR(EINVAL);

    }

    /* initialize libspeex */

    s->enc_state = speex_encoder_init(mode);

    if (!s->enc_state) {

        av_log(avctx, AV_LOG_ERROR, "Error initializing libspeex\n");

        return -1;

    }

    speex_init_header(&s->header, avctx->sample_rate, avctx->channels, mode);

    /* rate control method and parameters */

    if (avctx->flags & CODEC_FLAG_QSCALE) {

        /* VBR */

        s->header.vbr = 1;

        s->vad = 1; /* VAD is always implicitly activated for VBR */

        speex_encoder_ctl(s->enc_state, SPEEX_SET_VBR, &s->header.vbr);

        s->vbr_quality = av_clipf(avctx->global_quality / (float)FF_QP2LAMBDA,

                                  0.0f, 10.0f);

        speex_encoder_ctl(s->enc_state, SPEEX_SET_VBR_QUALITY, &s->vbr_quality);

    } else {

        s->header.bitrate = avctx->bit_rate;

        if (avctx->bit_rate > 0) {

            /* CBR or ABR by bitrate */

            if (s->abr) {

                speex_encoder_ctl(s->enc_state, SPEEX_SET_ABR,

                                  &s->header.bitrate);

                speex_encoder_ctl(s->enc_state, SPEEX_GET_ABR,

                                  &s->header.bitrate);

            } else {

                speex_encoder_ctl(s->enc_state, SPEEX_SET_BITRATE,

                                  &s->header.bitrate);

                speex_encoder_ctl(s->enc_state, SPEEX_GET_BITRATE,

                                  &s->header.bitrate);

            }

        } else {

            /* CBR by quality */

            speex_encoder_ctl(s->enc_state, SPEEX_SET_QUALITY,

                              &s->cbr_quality);

            speex_encoder_ctl(s->enc_state, SPEEX_GET_BITRATE,

                              &s->header.bitrate);

        }

        /* stereo side information adds about 800 bps to the base bitrate */

        /* TODO: this should be calculated exactly */

        avctx->bit_rate = s->header.bitrate + (avctx->channels == 2 ? 800 : 0);

    }

    /* VAD is activated with VBR or can be turned on by itself */

    if (s->vad)

        speex_encoder_ctl(s->enc_state, SPEEX_SET_VAD, &s->vad);

    /* Activiting Discontinuous Transmission */

    if (s->dtx) {

        speex_encoder_ctl(s->enc_state, SPEEX_SET_DTX, &s->dtx);

        if (!(s->abr || s->vad || s->header.vbr))

            av_log(avctx, AV_LOG_WARNING, "DTX is not much of use without ABR, VAD or VBR\n");

    }

    /* set encoding complexity */

    if (avctx->compression_level > FF_COMPRESSION_DEFAULT) {

        complexity = av_clip(avctx->compression_level, 0, 10);

        speex_encoder_ctl(s->enc_state, SPEEX_SET_COMPLEXITY, &complexity);

    }

    speex_encoder_ctl(s->enc_state, SPEEX_GET_COMPLEXITY, &complexity);

    avctx->compression_level = complexity;

    /* set packet size */

    avctx->frame_size = s->header.frame_size;

    s->header.frames_per_packet = s->frames_per_packet;

    /* set encoding delay */

    speex_encoder_ctl(s->enc_state, SPEEX_GET_LOOKAHEAD, &avctx->delay);

    ff_af_queue_init(avctx, &s->afq);

    /* create header packet bytes from header struct */

    /* note: libspeex allocates the memory for header_data, which is freed

             below with speex_header_free() */

    header_data = speex_header_to_packet(&s->header, &header_size);

    /* allocate extradata and coded_frame */

    avctx->extradata   = av_malloc(header_size + FF_INPUT_BUFFER_PADDING_SIZE);

    if (!avctx->extradata) {

        speex_header_free(header_data);

        speex_encoder_destroy(s->enc_state);

        av_log(avctx, AV_LOG_ERROR, "memory allocation error\n");

        return AVERROR(ENOMEM);

    }

    /* copy header packet to extradata */

    memcpy(avctx->extradata, header_data, header_size);

    avctx->extradata_size = header_size;

    speex_header_free(header_data);

    /* init libspeex bitwriter */

    speex_bits_init(&s->bits);

    print_enc_params(avctx, s);

    return 0;

}

static int encode_frame(AVCodecContext *avctx, AVPacket *avpkt,

                        const AVFrame *frame, int *got_packet_ptr)

{

    LibSpeexEncContext *s = avctx->priv_data;

    int16_t *samples      = frame ? (int16_t *)frame->data[0] : NULL;

    int ret;

    if (samples) {

        /* encode Speex frame */

        if (avctx->channels == 2)

            speex_encode_stereo_int(samples, s->header.frame_size, &s->bits);

        speex_encode_int(s->enc_state, samples, &s->bits);

        s->pkt_frame_count++;

        if ((ret = ff_af_queue_add(&s->afq, frame)) < 0)

            return ret;

    } else {

        /* handle end-of-stream */

        if (!s->pkt_frame_count)

            return 0;

        /* add extra terminator codes for unused frames in last packet */

        while (s->pkt_frame_count < s->frames_per_packet) {

            speex_bits_pack(&s->bits, 15, 5);

            s->pkt_frame_count++;

        }

    }

    /* write output if all frames for the packet have been encoded */

    if (s->pkt_frame_count == s->frames_per_packet) {

        s->pkt_frame_count = 0;

        if ((ret = ff_alloc_packet2(avctx, avpkt, speex_bits_nbytes(&s->bits))) < 0)

            return ret;

        ret = speex_bits_write(&s->bits, avpkt->data, avpkt->size);

        speex_bits_reset(&s->bits);

        /* Get the next frame pts/duration */

        ff_af_queue_remove(&s->afq, s->frames_per_packet * avctx->frame_size,

                           &avpkt->pts, &avpkt->duration);

        avpkt->size = ret;

        *got_packet_ptr = 1;

        return 0;

    }

    return 0;

}

static av_cold int encode_close(AVCodecContext *avctx)

{

    LibSpeexEncContext *s = avctx->priv_data;

    speex_bits_destroy(&s->bits);

    speex_encoder_destroy(s->enc_state);

    ff_af_queue_close(&s->afq);

    av_freep(&avctx->extradata);

    return 0;

}

#define OFFSET(x) offsetof(LibSpeexEncContext, x)

#define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM

static const AVOption options[] = {

    { "abr",               "Use average bit rate",                      OFFSET(abr),               AV_OPT_TYPE_INT, { .i64 = 0 }, 0,   1, AE },

    { "cbr_quality",       "Set quality value (0 to 10) for CBR",       OFFSET(cbr_quality),       AV_OPT_TYPE_INT, { .i64 = 8 }, 0,  10, AE },

    { "frames_per_packet", "Number of frames to encode in each packet", OFFSET(frames_per_packet), AV_OPT_TYPE_INT, { .i64 = 1 }, 1,   8, AE },

    { "vad",               "Voice Activity Detection",                  OFFSET(vad),               AV_OPT_TYPE_INT, { .i64 = 0 }, 0,   1, AE },

    { "dtx",               "Discontinuous Transmission",                OFFSET(dtx),               AV_OPT_TYPE_INT, { .i64 = 0 }, 0,   1, AE },

    { NULL },

};

static const AVClass speex_class = {

    .class_name = "libspeex",

    .item_name  = av_default_item_name,

    .option     = options,

    .version    = LIBAVUTIL_VERSION_INT,

};

static const AVCodecDefault defaults[] = {

    { "b",                 "0" },

    { "compression_level", "3" },

    { NULL },

};

AVCodec ff_libspeex_encoder = {

    .name           = "libspeex",

    .long_name      = NULL_IF_CONFIG_SMALL("libspeex Speex"),

    .type           = AVMEDIA_TYPE_AUDIO,

    .id             = AV_CODEC_ID_SPEEX,

    .priv_data_size = sizeof(LibSpeexEncContext),

    .init           = encode_init,

    .encode2        = encode_frame,

    .close          = encode_close,

    .capabilities   = CODEC_CAP_DELAY,

    .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,

                                                     AV_SAMPLE_FMT_NONE },

    .channel_layouts = (const uint64_t[]){ AV_CH_LAYOUT_MONO,

                                           AV_CH_LAYOUT_STEREO,

    .supported_samplerates = (const int[]){ 8000, 16000, 32000, 0 },

    .priv_class     = &speex_class,

    .defaults       = defaults,

};