1/*
2 * Copyright (C) 2009 Justin Ruggles
3 * Copyright (c) 2009 Xuggle Incorporated
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * libspeex Speex audio encoder
25 *
26 * Usage Guide
27 * This explains the values that need to be set prior to initialization in
28 * order to control various encoding parameters.
29 *
30 * Channels
31 *     Speex only supports mono or stereo, so avctx->ch_layout.nb_channels must
32 *     be set to 1 or 2.
33 *
34 * Sample Rate / Encoding Mode
35 *     Speex has 3 modes, each of which uses a specific sample rate.
36 *         narrowband     :  8 kHz
37 *         wideband       : 16 kHz
38 *         ultra-wideband : 32 kHz
39 *     avctx->sample_rate must be set to one of these 3 values.  This will be
40 *     used to set the encoding mode.
41 *
42 * Rate Control
43 *     VBR mode is turned on by setting AV_CODEC_FLAG_QSCALE in avctx->flags.
44 *     avctx->global_quality is used to set the encoding quality.
45 *     For CBR mode, avctx->bit_rate can be used to set the constant bitrate.
46 *     Alternatively, the 'cbr_quality' option can be set from 0 to 10 to set
47 *     a constant bitrate based on quality.
48 *     For ABR mode, set avctx->bit_rate and set the 'abr' option to 1.
49 *     Approx. Bitrate Range:
50 *         narrowband     : 2400 - 25600 bps
51 *         wideband       : 4000 - 43200 bps
52 *         ultra-wideband : 4400 - 45200 bps
53 *
54 * Complexity
55 *     Encoding complexity is controlled by setting avctx->compression_level.
56 *     The valid range is 0 to 10.  A higher setting gives generally better
57 *     quality at the expense of encoding speed.  This does not affect the
58 *     bit rate.
59 *
60 * Frames-per-Packet
61 *     The encoder defaults to using 1 frame-per-packet.  However, it is
62 *     sometimes desirable to use multiple frames-per-packet to reduce the
63 *     amount of container overhead.  This can be done by setting the
64 *     'frames_per_packet' option to a value 1 to 8.
65 *
66 *
67 * Optional features
68 * Speex encoder supports several optional features, which can be useful
69 * for some conditions.
70 *
71 * Voice Activity Detection
72 *     When enabled, voice activity detection detects whether the audio
73 *     being encoded is speech or silence/background noise. VAD is always
74 *     implicitly activated when encoding in VBR, so the option is only useful
75 *     in non-VBR operation. In this case, Speex detects non-speech periods and
76 *     encodes them with just enough bits to reproduce the background noise.
77 *
78 * Discontinuous Transmission (DTX)
79 *     DTX is an addition to VAD/VBR operation, that makes it possible to stop transmitting
80 *     completely when the background noise is stationary.
81 *     In file-based operation only 5 bits are used for such frames.
82 */
83
84#include <speex/speex.h>
85#include <speex/speex_header.h>
86#include <speex/speex_stereo.h>
87
88#include "libavutil/channel_layout.h"
89#include "libavutil/common.h"
90#include "libavutil/opt.h"
91#include "avcodec.h"
92#include "codec_internal.h"
93#include "encode.h"
94#include "audio_frame_queue.h"
95
96/* TODO: Think about converting abr, vad, dtx and such flags to a bit field */
97typedef struct LibSpeexEncContext {
98    AVClass *class;             ///< AVClass for private options
99    SpeexBits bits;             ///< libspeex bitwriter context
100    SpeexHeader header;         ///< libspeex header struct
101    void *enc_state;            ///< libspeex encoder state
102    int frames_per_packet;      ///< number of frames to encode in each packet
103    float vbr_quality;          ///< VBR quality 0.0 to 10.0
104    int cbr_quality;            ///< CBR quality 0 to 10
105    int abr;                    ///< flag to enable ABR
106    int vad;                    ///< flag to enable VAD
107    int dtx;                    ///< flag to enable DTX
108    int pkt_frame_count;        ///< frame count for the current packet
109    AudioFrameQueue afq;        ///< frame queue
110} LibSpeexEncContext;
111
112static av_cold void print_enc_params(AVCodecContext *avctx,
113                                     LibSpeexEncContext *s)
114{
115    const char *mode_str = "unknown";
116
117    av_log(avctx, AV_LOG_DEBUG, "channels: %d\n", avctx->ch_layout.nb_channels);
118    switch (s->header.mode) {
119    case SPEEX_MODEID_NB:  mode_str = "narrowband";     break;
120    case SPEEX_MODEID_WB:  mode_str = "wideband";       break;
121    case SPEEX_MODEID_UWB: mode_str = "ultra-wideband"; break;
122    }
123    av_log(avctx, AV_LOG_DEBUG, "mode: %s\n", mode_str);
124    if (s->header.vbr) {
125        av_log(avctx, AV_LOG_DEBUG, "rate control: VBR\n");
126        av_log(avctx, AV_LOG_DEBUG, "  quality: %f\n", s->vbr_quality);
127    } else if (s->abr) {
128        av_log(avctx, AV_LOG_DEBUG, "rate control: ABR\n");
129        av_log(avctx, AV_LOG_DEBUG, "  bitrate: %"PRId64" bps\n", avctx->bit_rate);
130    } else {
131        av_log(avctx, AV_LOG_DEBUG, "rate control: CBR\n");
132        av_log(avctx, AV_LOG_DEBUG, "  bitrate: %"PRId64" bps\n", avctx->bit_rate);
133    }
134    av_log(avctx, AV_LOG_DEBUG, "complexity: %d\n",
135           avctx->compression_level);
136    av_log(avctx, AV_LOG_DEBUG, "frame size: %d samples\n",
137           avctx->frame_size);
138    av_log(avctx, AV_LOG_DEBUG, "frames per packet: %d\n",
139           s->frames_per_packet);
140    av_log(avctx, AV_LOG_DEBUG, "packet size: %d\n",
141           avctx->frame_size * s->frames_per_packet);
142    av_log(avctx, AV_LOG_DEBUG, "voice activity detection: %d\n", s->vad);
143    av_log(avctx, AV_LOG_DEBUG, "discontinuous transmission: %d\n", s->dtx);
144}
145
146static av_cold int encode_init(AVCodecContext *avctx)
147{
148    LibSpeexEncContext *s = avctx->priv_data;
149    int channels = avctx->ch_layout.nb_channels;
150    const SpeexMode *mode;
151    uint8_t *header_data;
152    int header_size;
153    int32_t complexity;
154
155    /* channels */
156    if (channels < 1 || channels > 2) {
157        av_log(avctx, AV_LOG_ERROR, "Invalid channels (%d). Only stereo and "
158               "mono are supported\n", channels);
159        return AVERROR(EINVAL);
160    }
161
162    /* sample rate and encoding mode */
163    switch (avctx->sample_rate) {
164    case  8000: mode = speex_lib_get_mode(SPEEX_MODEID_NB);  break;
165    case 16000: mode = speex_lib_get_mode(SPEEX_MODEID_WB);  break;
166    case 32000: mode = speex_lib_get_mode(SPEEX_MODEID_UWB); break;
167    default:
168        av_log(avctx, AV_LOG_ERROR, "Sample rate of %d Hz is not supported. "
169               "Resample to 8, 16, or 32 kHz.\n", avctx->sample_rate);
170        return AVERROR(EINVAL);
171    }
172
173    /* initialize libspeex */
174    s->enc_state = speex_encoder_init(mode);
175    if (!s->enc_state) {
176        av_log(avctx, AV_LOG_ERROR, "Error initializing libspeex\n");
177        return -1;
178    }
179    speex_init_header(&s->header, avctx->sample_rate, channels, mode);
180
181    /* rate control method and parameters */
182    if (avctx->flags & AV_CODEC_FLAG_QSCALE) {
183        /* VBR */
184        s->header.vbr = 1;
185        s->vad = 1; /* VAD is always implicitly activated for VBR */
186        speex_encoder_ctl(s->enc_state, SPEEX_SET_VBR, &s->header.vbr);
187        s->vbr_quality = av_clipf(avctx->global_quality / (float)FF_QP2LAMBDA,
188                                  0.0f, 10.0f);
189        speex_encoder_ctl(s->enc_state, SPEEX_SET_VBR_QUALITY, &s->vbr_quality);
190    } else {
191        s->header.bitrate = avctx->bit_rate;
192        if (avctx->bit_rate > 0) {
193            /* CBR or ABR by bitrate */
194            if (s->abr) {
195                speex_encoder_ctl(s->enc_state, SPEEX_SET_ABR,
196                                  &s->header.bitrate);
197                speex_encoder_ctl(s->enc_state, SPEEX_GET_ABR,
198                                  &s->header.bitrate);
199            } else {
200                speex_encoder_ctl(s->enc_state, SPEEX_SET_BITRATE,
201                                  &s->header.bitrate);
202                speex_encoder_ctl(s->enc_state, SPEEX_GET_BITRATE,
203                                  &s->header.bitrate);
204            }
205        } else {
206            /* CBR by quality */
207            speex_encoder_ctl(s->enc_state, SPEEX_SET_QUALITY,
208                              &s->cbr_quality);
209            speex_encoder_ctl(s->enc_state, SPEEX_GET_BITRATE,
210                              &s->header.bitrate);
211        }
212        /* stereo side information adds about 800 bps to the base bitrate */
213        /* TODO: this should be calculated exactly */
214        avctx->bit_rate = s->header.bitrate + (channels == 2 ? 800 : 0);
215    }
216
217    /* VAD is activated with VBR or can be turned on by itself */
218    if (s->vad)
219        speex_encoder_ctl(s->enc_state, SPEEX_SET_VAD, &s->vad);
220
221    /* Activating Discontinuous Transmission */
222    if (s->dtx) {
223        speex_encoder_ctl(s->enc_state, SPEEX_SET_DTX, &s->dtx);
224        if (!(s->abr || s->vad || s->header.vbr))
225            av_log(avctx, AV_LOG_WARNING, "DTX is not much of use without ABR, VAD or VBR\n");
226    }
227
228    /* set encoding complexity */
229    if (avctx->compression_level > FF_COMPRESSION_DEFAULT) {
230        complexity = av_clip(avctx->compression_level, 0, 10);
231        speex_encoder_ctl(s->enc_state, SPEEX_SET_COMPLEXITY, &complexity);
232    }
233    speex_encoder_ctl(s->enc_state, SPEEX_GET_COMPLEXITY, &complexity);
234    avctx->compression_level = complexity;
235
236    /* set packet size */
237    avctx->frame_size = s->header.frame_size;
238    s->header.frames_per_packet = s->frames_per_packet;
239
240    /* set encoding delay */
241    speex_encoder_ctl(s->enc_state, SPEEX_GET_LOOKAHEAD, &avctx->initial_padding);
242    ff_af_queue_init(avctx, &s->afq);
243
244    /* create header packet bytes from header struct */
245    /* note: libspeex allocates the memory for header_data, which is freed
246             below with speex_header_free() */
247    header_data = speex_header_to_packet(&s->header, &header_size);
248
249    /* allocate extradata */
250    avctx->extradata = av_malloc(header_size + AV_INPUT_BUFFER_PADDING_SIZE);
251    if (!avctx->extradata) {
252        speex_header_free(header_data);
253        speex_encoder_destroy(s->enc_state);
254        av_log(avctx, AV_LOG_ERROR, "memory allocation error\n");
255        return AVERROR(ENOMEM);
256    }
257
258    /* copy header packet to extradata */
259    memcpy(avctx->extradata, header_data, header_size);
260    avctx->extradata_size = header_size;
261    speex_header_free(header_data);
262
263    /* init libspeex bitwriter */
264    speex_bits_init(&s->bits);
265
266    print_enc_params(avctx, s);
267    return 0;
268}
269
270static int encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
271                        const AVFrame *frame, int *got_packet_ptr)
272{
273    LibSpeexEncContext *s = avctx->priv_data;
274    int16_t *samples      = frame ? (int16_t *)frame->data[0] : NULL;
275    int ret;
276
277    if (samples) {
278        /* encode Speex frame */
279        if (avctx->ch_layout.nb_channels == 2)
280            speex_encode_stereo_int(samples, s->header.frame_size, &s->bits);
281        speex_encode_int(s->enc_state, samples, &s->bits);
282        s->pkt_frame_count++;
283        if ((ret = ff_af_queue_add(&s->afq, frame)) < 0)
284            return ret;
285    } else {
286        /* handle end-of-stream */
287        if (!s->pkt_frame_count)
288            return 0;
289        /* add extra terminator codes for unused frames in last packet */
290        while (s->pkt_frame_count < s->frames_per_packet) {
291            speex_bits_pack(&s->bits, 15, 5);
292            s->pkt_frame_count++;
293        }
294    }
295
296    /* write output if all frames for the packet have been encoded */
297    if (s->pkt_frame_count == s->frames_per_packet) {
298        s->pkt_frame_count = 0;
299        if ((ret = ff_alloc_packet(avctx, avpkt, speex_bits_nbytes(&s->bits))) < 0)
300            return ret;
301        ret = speex_bits_write(&s->bits, avpkt->data, avpkt->size);
302        speex_bits_reset(&s->bits);
303
304        /* Get the next frame pts/duration */
305        ff_af_queue_remove(&s->afq, s->frames_per_packet * avctx->frame_size,
306                           &avpkt->pts, &avpkt->duration);
307
308        avpkt->size = ret;
309        *got_packet_ptr = 1;
310        return 0;
311    }
312    return 0;
313}
314
315static av_cold int encode_close(AVCodecContext *avctx)
316{
317    LibSpeexEncContext *s = avctx->priv_data;
318
319    speex_bits_destroy(&s->bits);
320    speex_encoder_destroy(s->enc_state);
321
322    ff_af_queue_close(&s->afq);
323
324    return 0;
325}
326
327#define OFFSET(x) offsetof(LibSpeexEncContext, x)
328#define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
329static const AVOption options[] = {
330    { "abr",               "Use average bit rate",                      OFFSET(abr),               AV_OPT_TYPE_INT, { .i64 = 0 }, 0,   1, AE },
331    { "cbr_quality",       "Set quality value (0 to 10) for CBR",       OFFSET(cbr_quality),       AV_OPT_TYPE_INT, { .i64 = 8 }, 0,  10, AE },
332    { "frames_per_packet", "Number of frames to encode in each packet", OFFSET(frames_per_packet), AV_OPT_TYPE_INT, { .i64 = 1 }, 1,   8, AE },
333    { "vad",               "Voice Activity Detection",                  OFFSET(vad),               AV_OPT_TYPE_INT, { .i64 = 0 }, 0,   1, AE },
334    { "dtx",               "Discontinuous Transmission",                OFFSET(dtx),               AV_OPT_TYPE_INT, { .i64 = 0 }, 0,   1, AE },
335    { NULL },
336};
337
338static const AVClass speex_class = {
339    .class_name = "libspeex",
340    .item_name  = av_default_item_name,
341    .option     = options,
342    .version    = LIBAVUTIL_VERSION_INT,
343};
344
345static const FFCodecDefault defaults[] = {
346    { "b",                 "0" },
347    { "compression_level", "3" },
348    { NULL },
349};
350
351const FFCodec ff_libspeex_encoder = {
352    .p.name         = "libspeex",
353    .p.long_name    = NULL_IF_CONFIG_SMALL("libspeex Speex"),
354    .p.type         = AVMEDIA_TYPE_AUDIO,
355    .p.id           = AV_CODEC_ID_SPEEX,
356    .priv_data_size = sizeof(LibSpeexEncContext),
357    .init           = encode_init,
358    FF_CODEC_ENCODE_CB(encode_frame),
359    .close          = encode_close,
360    .p.capabilities = AV_CODEC_CAP_DELAY,
361    .p.sample_fmts  = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
362                                                     AV_SAMPLE_FMT_NONE },
363#if FF_API_OLD_CHANNEL_LAYOUT
364    .p.channel_layouts = (const uint64_t[]){ AV_CH_LAYOUT_MONO,
365                                           AV_CH_LAYOUT_STEREO,
366                                           0 },
367#endif
368    .p.ch_layouts    = (const AVChannelLayout[]) { AV_CHANNEL_LAYOUT_MONO,
369                                                   AV_CHANNEL_LAYOUT_STEREO,
370                                                   { 0 },
371    },
372    .p.supported_samplerates = (const int[]){ 8000, 16000, 32000, 0 },
373    .p.priv_class   = &speex_class,
374    .defaults       = defaults,
375    .p.wrapper_name = "libspeex",
376};
377