/*

  * 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 <speex/speex.h>
 #include <speex/speex_header.h>
 #include <speex/speex_stereo.h>

 #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 LibSpeexEncContext {

     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->initial_padding);

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

     .priv_class     = &speex_class,

     .defaults       = defaults,

 };