/*
* 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 {
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,
0 },
.supported_samplerates = (const int[]){ 8000, 16000, 32000, 0 },
.priv_class = &speex_class,
.defaults = defaults,
};