1/*
2 * Interface to libmp3lame for mp3 encoding
3 * Copyright (c) 2002 Lennert Buytenhek <buytenh@gnu.org>
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 libavcodec/libmp3lame.c
24 * Interface to libmp3lame for mp3 encoding.
25 */
26
27#include "avcodec.h"
28#include "mpegaudio.h"
29#include <lame/lame.h>
30
31#define BUFFER_SIZE (7200 + 2*MPA_FRAME_SIZE + MPA_FRAME_SIZE/4)
32typedef struct Mp3AudioContext {
33    lame_global_flags *gfp;
34    int stereo;
35    uint8_t buffer[BUFFER_SIZE];
36    int buffer_index;
37} Mp3AudioContext;
38
39static av_cold int MP3lame_encode_init(AVCodecContext *avctx)
40{
41    Mp3AudioContext *s = avctx->priv_data;
42
43    if (avctx->channels > 2)
44        return -1;
45
46    s->stereo = avctx->channels > 1 ? 1 : 0;
47
48    if ((s->gfp = lame_init()) == NULL)
49        goto err;
50    lame_set_in_samplerate(s->gfp, avctx->sample_rate);
51    lame_set_out_samplerate(s->gfp, avctx->sample_rate);
52    lame_set_num_channels(s->gfp, avctx->channels);
53    if(avctx->compression_level == FF_COMPRESSION_DEFAULT) {
54        lame_set_quality(s->gfp, 5);
55    } else {
56        lame_set_quality(s->gfp, avctx->compression_level);
57    }
58    /* lame 3.91 doesn't work in mono */
59    lame_set_mode(s->gfp, JOINT_STEREO);
60    lame_set_brate(s->gfp, avctx->bit_rate/1000);
61    if(avctx->flags & CODEC_FLAG_QSCALE) {
62        lame_set_brate(s->gfp, 0);
63        lame_set_VBR(s->gfp, vbr_default);
64        lame_set_VBR_q(s->gfp, avctx->global_quality / (float)FF_QP2LAMBDA);
65    }
66    lame_set_bWriteVbrTag(s->gfp,0);
67    lame_set_disable_reservoir(s->gfp, avctx->flags2 & CODEC_FLAG2_BIT_RESERVOIR ? 0 : 1);
68    if (lame_init_params(s->gfp) < 0)
69        goto err_close;
70
71    avctx->frame_size = lame_get_framesize(s->gfp);
72
73    avctx->coded_frame= avcodec_alloc_frame();
74    avctx->coded_frame->key_frame= 1;
75
76    return 0;
77
78err_close:
79    lame_close(s->gfp);
80err:
81    return -1;
82}
83
84static const int sSampleRates[3] = {
85    44100, 48000,  32000
86};
87
88static const int sBitRates[2][3][15] = {
89    {   {  0, 32, 64, 96,128,160,192,224,256,288,320,352,384,416,448},
90        {  0, 32, 48, 56, 64, 80, 96,112,128,160,192,224,256,320,384},
91        {  0, 32, 40, 48, 56, 64, 80, 96,112,128,160,192,224,256,320}
92    },
93    {   {  0, 32, 48, 56, 64, 80, 96,112,128,144,160,176,192,224,256},
94        {  0,  8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160},
95        {  0,  8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160}
96    },
97};
98
99static const int sSamplesPerFrame[2][3] =
100{
101    {  384,     1152,    1152 },
102    {  384,     1152,     576 }
103};
104
105static const int sBitsPerSlot[3] = {
106    32,
107    8,
108    8
109};
110
111static int mp3len(void *data, int *samplesPerFrame, int *sampleRate)
112{
113    uint32_t header = AV_RB32(data);
114    int layerID = 3 - ((header >> 17) & 0x03);
115    int bitRateID = ((header >> 12) & 0x0f);
116    int sampleRateID = ((header >> 10) & 0x03);
117    int bitsPerSlot = sBitsPerSlot[layerID];
118    int isPadded = ((header >> 9) & 0x01);
119    static int const mode_tab[4]= {2,3,1,0};
120    int mode= mode_tab[(header >> 19) & 0x03];
121    int mpeg_id= mode>0;
122    int temp0, temp1, bitRate;
123
124    if ( (( header >> 21 ) & 0x7ff) != 0x7ff || mode == 3 || layerID==3 || sampleRateID==3) {
125        return -1;
126    }
127
128    if(!samplesPerFrame) samplesPerFrame= &temp0;
129    if(!sampleRate     ) sampleRate     = &temp1;
130
131//    *isMono = ((header >>  6) & 0x03) == 0x03;
132
133    *sampleRate = sSampleRates[sampleRateID]>>mode;
134    bitRate = sBitRates[mpeg_id][layerID][bitRateID] * 1000;
135    *samplesPerFrame = sSamplesPerFrame[mpeg_id][layerID];
136//av_log(NULL, AV_LOG_DEBUG, "sr:%d br:%d spf:%d l:%d m:%d\n", *sampleRate, bitRate, *samplesPerFrame, layerID, mode);
137
138    return *samplesPerFrame * bitRate / (bitsPerSlot * *sampleRate) + isPadded;
139}
140
141static int MP3lame_encode_frame(AVCodecContext *avctx,
142                                unsigned char *frame, int buf_size, void *data)
143{
144    Mp3AudioContext *s = avctx->priv_data;
145    int len;
146    int lame_result;
147
148    /* lame 3.91 dies on '1-channel interleaved' data */
149
150    if(data){
151        if (s->stereo) {
152            lame_result = lame_encode_buffer_interleaved(
153                s->gfp,
154                data,
155                avctx->frame_size,
156                s->buffer + s->buffer_index,
157                BUFFER_SIZE - s->buffer_index
158                );
159        } else {
160            lame_result = lame_encode_buffer(
161                s->gfp,
162                data,
163                data,
164                avctx->frame_size,
165                s->buffer + s->buffer_index,
166                BUFFER_SIZE - s->buffer_index
167                );
168        }
169    }else{
170        lame_result= lame_encode_flush(
171                s->gfp,
172                s->buffer + s->buffer_index,
173                BUFFER_SIZE - s->buffer_index
174                );
175    }
176
177    if(lame_result < 0){
178        if(lame_result==-1) {
179            /* output buffer too small */
180            av_log(avctx, AV_LOG_ERROR, "lame: output buffer too small (buffer index: %d, free bytes: %d)\n", s->buffer_index, BUFFER_SIZE - s->buffer_index);
181        }
182        return -1;
183    }
184
185    s->buffer_index += lame_result;
186
187    if(s->buffer_index<4)
188        return 0;
189
190    len= mp3len(s->buffer, NULL, NULL);
191//av_log(avctx, AV_LOG_DEBUG, "in:%d packet-len:%d index:%d\n", avctx->frame_size, len, s->buffer_index);
192    if(len <= s->buffer_index){
193        memcpy(frame, s->buffer, len);
194        s->buffer_index -= len;
195
196        memmove(s->buffer, s->buffer+len, s->buffer_index);
197            //FIXME fix the audio codec API, so we do not need the memcpy()
198/*for(i=0; i<len; i++){
199    av_log(avctx, AV_LOG_DEBUG, "%2X ", frame[i]);
200}*/
201        return len;
202    }else
203        return 0;
204}
205
206static av_cold int MP3lame_encode_close(AVCodecContext *avctx)
207{
208    Mp3AudioContext *s = avctx->priv_data;
209
210    av_freep(&avctx->coded_frame);
211
212    lame_close(s->gfp);
213    return 0;
214}
215
216
217AVCodec libmp3lame_encoder = {
218    "libmp3lame",
219    CODEC_TYPE_AUDIO,
220    CODEC_ID_MP3,
221    sizeof(Mp3AudioContext),
222    MP3lame_encode_init,
223    MP3lame_encode_frame,
224    MP3lame_encode_close,
225    .capabilities= CODEC_CAP_DELAY,
226    .sample_fmts = (enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
227    .long_name= NULL_IF_CONFIG_SMALL("libmp3lame MP3 (MPEG audio layer 3)"),
228};
229