370 lines
14 KiB
C
370 lines
14 KiB
C
/*
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* Copyright (C) 2009 Justin Ruggles
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* Copyright (c) 2009 Xuggle Incorporated
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* libspeex Speex audio encoder
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*
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* Usage Guide
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* This explains the values that need to be set prior to initialization in
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* order to control various encoding parameters.
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*
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* Channels
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* Speex only supports mono or stereo, so avctx->channels must be set to
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* 1 or 2.
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*
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* Sample Rate / Encoding Mode
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* Speex has 3 modes, each of which uses a specific sample rate.
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* narrowband : 8 kHz
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* wideband : 16 kHz
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* ultra-wideband : 32 kHz
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* avctx->sample_rate must be set to one of these 3 values. This will be
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* used to set the encoding mode.
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*
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* Rate Control
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* VBR mode is turned on by setting AV_CODEC_FLAG_QSCALE in avctx->flags.
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* avctx->global_quality is used to set the encoding quality.
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* For CBR mode, avctx->bit_rate can be used to set the constant bitrate.
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* Alternatively, the 'cbr_quality' option can be set from 0 to 10 to set
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* a constant bitrate based on quality.
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* For ABR mode, set avctx->bit_rate and set the 'abr' option to 1.
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* Approx. Bitrate Range:
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* narrowband : 2400 - 25600 bps
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* wideband : 4000 - 43200 bps
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* ultra-wideband : 4400 - 45200 bps
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*
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* Complexity
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* Encoding complexity is controlled by setting avctx->compression_level.
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* The valid range is 0 to 10. A higher setting gives generally better
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* quality at the expense of encoding speed. This does not affect the
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* bit rate.
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*
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* Frames-per-Packet
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* The encoder defaults to using 1 frame-per-packet. However, it is
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* sometimes desirable to use multiple frames-per-packet to reduce the
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* amount of container overhead. This can be done by setting the
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* 'frames_per_packet' option to a value 1 to 8.
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*
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*
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* Optional features
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* Speex encoder supports several optional features, which can be useful
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* for some conditions.
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*
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* Voice Activity Detection
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* When enabled, voice activity detection detects whether the audio
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* being encoded is speech or silence/background noise. VAD is always
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* implicitly activated when encoding in VBR, so the option is only useful
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* in non-VBR operation. In this case, Speex detects non-speech periods and
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* encodes them with just enough bits to reproduce the background noise.
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*
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* Discontinuous Transmission (DTX)
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* DTX is an addition to VAD/VBR operation, that allows to stop transmitting
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* completely when the background noise is stationary.
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* In file-based operation only 5 bits are used for such frames.
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*/
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#include <speex/speex.h>
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#include <speex/speex_header.h>
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#include <speex/speex_stereo.h>
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#include "libavutil/channel_layout.h"
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#include "libavutil/common.h"
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#include "libavutil/opt.h"
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#include "avcodec.h"
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#include "internal.h"
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#include "audio_frame_queue.h"
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typedef struct LibSpeexEncContext {
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AVClass *class; ///< AVClass for private options
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SpeexBits bits; ///< libspeex bitwriter context
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SpeexHeader header; ///< libspeex header struct
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void *enc_state; ///< libspeex encoder state
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int frames_per_packet; ///< number of frames to encode in each packet
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float vbr_quality; ///< VBR quality 0.0 to 10.0
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int cbr_quality; ///< CBR quality 0 to 10
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int abr; ///< flag to enable ABR
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int vad; ///< flag to enable VAD
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int dtx; ///< flag to enable DTX
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int pkt_frame_count; ///< frame count for the current packet
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AudioFrameQueue afq; ///< frame queue
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} LibSpeexEncContext;
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static av_cold void print_enc_params(AVCodecContext *avctx,
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LibSpeexEncContext *s)
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{
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const char *mode_str = "unknown";
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av_log(avctx, AV_LOG_DEBUG, "channels: %d\n", avctx->channels);
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switch (s->header.mode) {
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case SPEEX_MODEID_NB: mode_str = "narrowband"; break;
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case SPEEX_MODEID_WB: mode_str = "wideband"; break;
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case SPEEX_MODEID_UWB: mode_str = "ultra-wideband"; break;
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}
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av_log(avctx, AV_LOG_DEBUG, "mode: %s\n", mode_str);
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if (s->header.vbr) {
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av_log(avctx, AV_LOG_DEBUG, "rate control: VBR\n");
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av_log(avctx, AV_LOG_DEBUG, " quality: %f\n", s->vbr_quality);
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} else if (s->abr) {
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av_log(avctx, AV_LOG_DEBUG, "rate control: ABR\n");
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av_log(avctx, AV_LOG_DEBUG, " bitrate: %d bps\n", avctx->bit_rate);
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} else {
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av_log(avctx, AV_LOG_DEBUG, "rate control: CBR\n");
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av_log(avctx, AV_LOG_DEBUG, " bitrate: %d bps\n", avctx->bit_rate);
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}
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av_log(avctx, AV_LOG_DEBUG, "complexity: %d\n",
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avctx->compression_level);
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av_log(avctx, AV_LOG_DEBUG, "frame size: %d samples\n",
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avctx->frame_size);
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av_log(avctx, AV_LOG_DEBUG, "frames per packet: %d\n",
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s->frames_per_packet);
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av_log(avctx, AV_LOG_DEBUG, "packet size: %d\n",
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avctx->frame_size * s->frames_per_packet);
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av_log(avctx, AV_LOG_DEBUG, "voice activity detection: %d\n", s->vad);
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av_log(avctx, AV_LOG_DEBUG, "discontinuous transmission: %d\n", s->dtx);
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}
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static av_cold int encode_init(AVCodecContext *avctx)
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{
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LibSpeexEncContext *s = avctx->priv_data;
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const SpeexMode *mode;
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uint8_t *header_data;
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int header_size;
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int32_t complexity;
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/* channels */
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if (avctx->channels < 1 || avctx->channels > 2) {
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av_log(avctx, AV_LOG_ERROR, "Invalid channels (%d). Only stereo and "
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"mono are supported\n", avctx->channels);
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return AVERROR(EINVAL);
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}
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/* sample rate and encoding mode */
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switch (avctx->sample_rate) {
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case 8000: mode = &speex_nb_mode; break;
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case 16000: mode = &speex_wb_mode; break;
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case 32000: mode = &speex_uwb_mode; break;
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default:
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av_log(avctx, AV_LOG_ERROR, "Sample rate of %d Hz is not supported. "
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"Resample to 8, 16, or 32 kHz.\n", avctx->sample_rate);
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return AVERROR(EINVAL);
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}
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/* initialize libspeex */
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s->enc_state = speex_encoder_init(mode);
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if (!s->enc_state) {
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av_log(avctx, AV_LOG_ERROR, "Error initializing libspeex\n");
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return -1;
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}
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speex_init_header(&s->header, avctx->sample_rate, avctx->channels, mode);
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/* rate control method and parameters */
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if (avctx->flags & AV_CODEC_FLAG_QSCALE) {
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/* VBR */
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s->header.vbr = 1;
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s->vad = 1; /* VAD is always implicitly activated for VBR */
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speex_encoder_ctl(s->enc_state, SPEEX_SET_VBR, &s->header.vbr);
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s->vbr_quality = av_clipf(avctx->global_quality / (float)FF_QP2LAMBDA,
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0.0f, 10.0f);
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speex_encoder_ctl(s->enc_state, SPEEX_SET_VBR_QUALITY, &s->vbr_quality);
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} else {
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s->header.bitrate = avctx->bit_rate;
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if (avctx->bit_rate > 0) {
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/* CBR or ABR by bitrate */
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if (s->abr) {
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speex_encoder_ctl(s->enc_state, SPEEX_SET_ABR,
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&s->header.bitrate);
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speex_encoder_ctl(s->enc_state, SPEEX_GET_ABR,
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&s->header.bitrate);
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} else {
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speex_encoder_ctl(s->enc_state, SPEEX_SET_BITRATE,
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&s->header.bitrate);
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speex_encoder_ctl(s->enc_state, SPEEX_GET_BITRATE,
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&s->header.bitrate);
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}
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} else {
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/* CBR by quality */
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speex_encoder_ctl(s->enc_state, SPEEX_SET_QUALITY,
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&s->cbr_quality);
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speex_encoder_ctl(s->enc_state, SPEEX_GET_BITRATE,
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&s->header.bitrate);
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}
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/* stereo side information adds about 800 bps to the base bitrate */
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/* TODO: this should be calculated exactly */
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avctx->bit_rate = s->header.bitrate + (avctx->channels == 2 ? 800 : 0);
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}
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/* VAD is activated with VBR or can be turned on by itself */
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if (s->vad)
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speex_encoder_ctl(s->enc_state, SPEEX_SET_VAD, &s->vad);
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/* Activiting Discontinuous Transmission */
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if (s->dtx) {
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speex_encoder_ctl(s->enc_state, SPEEX_SET_DTX, &s->dtx);
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if (!(s->abr || s->vad || s->header.vbr))
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av_log(avctx, AV_LOG_WARNING, "DTX is not much of use without ABR, VAD or VBR\n");
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}
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/* set encoding complexity */
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if (avctx->compression_level > FF_COMPRESSION_DEFAULT) {
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complexity = av_clip(avctx->compression_level, 0, 10);
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speex_encoder_ctl(s->enc_state, SPEEX_SET_COMPLEXITY, &complexity);
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}
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speex_encoder_ctl(s->enc_state, SPEEX_GET_COMPLEXITY, &complexity);
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avctx->compression_level = complexity;
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/* set packet size */
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avctx->frame_size = s->header.frame_size;
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s->header.frames_per_packet = s->frames_per_packet;
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/* set encoding delay */
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speex_encoder_ctl(s->enc_state, SPEEX_GET_LOOKAHEAD, &avctx->initial_padding);
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ff_af_queue_init(avctx, &s->afq);
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/* create header packet bytes from header struct */
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/* note: libspeex allocates the memory for header_data, which is freed
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below with speex_header_free() */
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header_data = speex_header_to_packet(&s->header, &header_size);
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/* allocate extradata */
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avctx->extradata = av_malloc(header_size + AV_INPUT_BUFFER_PADDING_SIZE);
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if (!avctx->extradata) {
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speex_header_free(header_data);
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speex_encoder_destroy(s->enc_state);
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av_log(avctx, AV_LOG_ERROR, "memory allocation error\n");
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return AVERROR(ENOMEM);
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}
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/* copy header packet to extradata */
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memcpy(avctx->extradata, header_data, header_size);
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avctx->extradata_size = header_size;
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speex_header_free(header_data);
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/* init libspeex bitwriter */
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speex_bits_init(&s->bits);
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print_enc_params(avctx, s);
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return 0;
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}
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static int encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
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const AVFrame *frame, int *got_packet_ptr)
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{
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LibSpeexEncContext *s = avctx->priv_data;
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int16_t *samples = frame ? (int16_t *)frame->data[0] : NULL;
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int ret;
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if (samples) {
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/* encode Speex frame */
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if (avctx->channels == 2)
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speex_encode_stereo_int(samples, s->header.frame_size, &s->bits);
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speex_encode_int(s->enc_state, samples, &s->bits);
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s->pkt_frame_count++;
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if ((ret = ff_af_queue_add(&s->afq, frame)) < 0)
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return ret;
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} else {
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/* handle end-of-stream */
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if (!s->pkt_frame_count)
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return 0;
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/* add extra terminator codes for unused frames in last packet */
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while (s->pkt_frame_count < s->frames_per_packet) {
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speex_bits_pack(&s->bits, 15, 5);
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s->pkt_frame_count++;
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}
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}
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/* write output if all frames for the packet have been encoded */
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if (s->pkt_frame_count == s->frames_per_packet) {
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s->pkt_frame_count = 0;
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if ((ret = ff_alloc_packet(avpkt, speex_bits_nbytes(&s->bits)))) {
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av_log(avctx, AV_LOG_ERROR, "Error getting output packet\n");
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return ret;
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}
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ret = speex_bits_write(&s->bits, avpkt->data, avpkt->size);
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speex_bits_reset(&s->bits);
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/* Get the next frame pts/duration */
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ff_af_queue_remove(&s->afq, s->frames_per_packet * avctx->frame_size,
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&avpkt->pts, &avpkt->duration);
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avpkt->size = ret;
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*got_packet_ptr = 1;
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return 0;
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}
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return 0;
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}
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static av_cold int encode_close(AVCodecContext *avctx)
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{
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LibSpeexEncContext *s = avctx->priv_data;
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speex_bits_destroy(&s->bits);
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speex_encoder_destroy(s->enc_state);
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ff_af_queue_close(&s->afq);
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av_freep(&avctx->extradata);
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return 0;
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}
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#define OFFSET(x) offsetof(LibSpeexEncContext, x)
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#define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
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static const AVOption options[] = {
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{ "abr", "Use average bit rate", OFFSET(abr), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, AE },
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{ "cbr_quality", "Set quality value (0 to 10) for CBR", OFFSET(cbr_quality), AV_OPT_TYPE_INT, { .i64 = 8 }, 0, 10, AE },
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{ "frames_per_packet", "Number of frames to encode in each packet", OFFSET(frames_per_packet), AV_OPT_TYPE_INT, { .i64 = 1 }, 1, 8, AE },
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{ "vad", "Voice Activity Detection", OFFSET(vad), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, AE },
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{ "dtx", "Discontinuous Transmission", OFFSET(dtx), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, AE },
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{ NULL },
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};
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static const AVClass class = {
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.class_name = "libspeex",
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.item_name = av_default_item_name,
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.option = options,
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.version = LIBAVUTIL_VERSION_INT,
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};
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static const AVCodecDefault defaults[] = {
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{ "b", "0" },
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{ "compression_level", "3" },
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{ NULL },
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};
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AVCodec ff_libspeex_encoder = {
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.name = "libspeex",
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.long_name = NULL_IF_CONFIG_SMALL("libspeex Speex"),
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.type = AVMEDIA_TYPE_AUDIO,
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.id = AV_CODEC_ID_SPEEX,
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.priv_data_size = sizeof(LibSpeexEncContext),
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.init = encode_init,
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.encode2 = encode_frame,
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.close = encode_close,
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.capabilities = AV_CODEC_CAP_DELAY,
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.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
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AV_SAMPLE_FMT_NONE },
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.channel_layouts = (const uint64_t[]){ AV_CH_LAYOUT_MONO,
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AV_CH_LAYOUT_STEREO,
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0 },
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.supported_samplerates = (const int[]){ 8000, 16000, 32000, 0 },
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.priv_class = &class,
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.defaults = defaults,
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};
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