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Rev | Author | Line No. | Line |
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6148 | serge | 1 | /* |
2 | * RoQ audio encoder |
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3 | * |
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4 | * Copyright (c) 2005 Eric Lasota |
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5 | * Based on RoQ specs (c)2001 Tim Ferguson |
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6 | * |
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7 | * This file is part of FFmpeg. |
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8 | * |
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9 | * FFmpeg is free software; you can redistribute it and/or |
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10 | * modify it under the terms of the GNU Lesser General Public |
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11 | * License as published by the Free Software Foundation; either |
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12 | * version 2.1 of the License, or (at your option) any later version. |
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13 | * |
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14 | * FFmpeg is distributed in the hope that it will be useful, |
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15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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17 | * Lesser General Public License for more details. |
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18 | * |
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19 | * You should have received a copy of the GNU Lesser General Public |
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20 | * License along with FFmpeg; if not, write to the Free Software |
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21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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22 | */ |
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23 | |||
24 | #include "avcodec.h" |
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25 | #include "bytestream.h" |
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26 | #include "internal.h" |
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27 | #include "mathops.h" |
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28 | |||
29 | #define ROQ_FRAME_SIZE 735 |
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30 | #define ROQ_HEADER_SIZE 8 |
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31 | |||
32 | #define MAX_DPCM (127*127) |
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33 | |||
34 | |||
35 | typedef struct |
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36 | { |
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37 | short lastSample[2]; |
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38 | int input_frames; |
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39 | int buffered_samples; |
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40 | int16_t *frame_buffer; |
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41 | int64_t first_pts; |
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42 | } ROQDPCMContext; |
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43 | |||
44 | |||
45 | static av_cold int roq_dpcm_encode_close(AVCodecContext *avctx) |
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46 | { |
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47 | ROQDPCMContext *context = avctx->priv_data; |
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48 | |||
49 | av_freep(&context->frame_buffer); |
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50 | |||
51 | return 0; |
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52 | } |
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53 | |||
54 | static av_cold int roq_dpcm_encode_init(AVCodecContext *avctx) |
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55 | { |
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56 | ROQDPCMContext *context = avctx->priv_data; |
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57 | int ret; |
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58 | |||
59 | if (avctx->channels > 2) { |
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60 | av_log(avctx, AV_LOG_ERROR, "Audio must be mono or stereo\n"); |
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61 | return AVERROR(EINVAL); |
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62 | } |
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63 | if (avctx->sample_rate != 22050) { |
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64 | av_log(avctx, AV_LOG_ERROR, "Audio must be 22050 Hz\n"); |
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65 | return AVERROR(EINVAL); |
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66 | } |
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67 | |||
68 | avctx->frame_size = ROQ_FRAME_SIZE; |
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69 | avctx->bit_rate = (ROQ_HEADER_SIZE + ROQ_FRAME_SIZE * avctx->channels) * |
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70 | (22050 / ROQ_FRAME_SIZE) * 8; |
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71 | |||
72 | context->frame_buffer = av_malloc(8 * ROQ_FRAME_SIZE * avctx->channels * |
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73 | sizeof(*context->frame_buffer)); |
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74 | if (!context->frame_buffer) { |
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75 | ret = AVERROR(ENOMEM); |
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76 | goto error; |
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77 | } |
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78 | |||
79 | context->lastSample[0] = context->lastSample[1] = 0; |
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80 | |||
81 | return 0; |
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82 | error: |
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83 | roq_dpcm_encode_close(avctx); |
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84 | return ret; |
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85 | } |
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86 | |||
87 | static unsigned char dpcm_predict(short *previous, short current) |
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88 | { |
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89 | int diff; |
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90 | int negative; |
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91 | int result; |
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92 | int predicted; |
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93 | |||
94 | diff = current - *previous; |
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95 | |||
96 | negative = diff<0; |
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97 | diff = FFABS(diff); |
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98 | |||
99 | if (diff >= MAX_DPCM) |
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100 | result = 127; |
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101 | else { |
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102 | result = ff_sqrt(diff); |
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103 | result += diff > result*result+result; |
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104 | } |
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105 | |||
106 | /* See if this overflows */ |
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107 | retry: |
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108 | diff = result*result; |
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109 | if (negative) |
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110 | diff = -diff; |
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111 | predicted = *previous + diff; |
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112 | |||
113 | /* If it overflows, back off a step */ |
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114 | if (predicted > 32767 || predicted < -32768) { |
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115 | result--; |
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116 | goto retry; |
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117 | } |
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118 | |||
119 | /* Add the sign bit */ |
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120 | result |= negative << 7; //if (negative) result |= 128; |
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121 | |||
122 | *previous = predicted; |
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123 | |||
124 | return result; |
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125 | } |
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126 | |||
127 | static int roq_dpcm_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, |
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128 | const AVFrame *frame, int *got_packet_ptr) |
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129 | { |
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130 | int i, stereo, data_size, ret; |
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131 | const int16_t *in = frame ? (const int16_t *)frame->data[0] : NULL; |
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132 | uint8_t *out; |
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133 | ROQDPCMContext *context = avctx->priv_data; |
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134 | |||
135 | stereo = (avctx->channels == 2); |
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136 | |||
137 | if (!in && context->input_frames >= 8) |
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138 | return 0; |
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139 | |||
140 | if (in && context->input_frames < 8) { |
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141 | memcpy(&context->frame_buffer[context->buffered_samples * avctx->channels], |
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142 | in, avctx->frame_size * avctx->channels * sizeof(*in)); |
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143 | context->buffered_samples += avctx->frame_size; |
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144 | if (context->input_frames == 0) |
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145 | context->first_pts = frame->pts; |
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146 | if (context->input_frames < 7) { |
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147 | context->input_frames++; |
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148 | return 0; |
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149 | } |
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150 | } |
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151 | if (context->input_frames < 8) { |
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152 | in = context->frame_buffer; |
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153 | } |
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154 | |||
155 | if (stereo) { |
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156 | context->lastSample[0] &= 0xFF00; |
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157 | context->lastSample[1] &= 0xFF00; |
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158 | } |
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159 | |||
160 | if (context->input_frames == 7) |
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161 | data_size = avctx->channels * context->buffered_samples; |
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162 | else |
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163 | data_size = avctx->channels * avctx->frame_size; |
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164 | |||
165 | if ((ret = ff_alloc_packet2(avctx, avpkt, ROQ_HEADER_SIZE + data_size)) < 0) |
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166 | return ret; |
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167 | out = avpkt->data; |
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168 | |||
169 | bytestream_put_byte(&out, stereo ? 0x21 : 0x20); |
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170 | bytestream_put_byte(&out, 0x10); |
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171 | bytestream_put_le32(&out, data_size); |
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172 | |||
173 | if (stereo) { |
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174 | bytestream_put_byte(&out, (context->lastSample[1])>>8); |
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175 | bytestream_put_byte(&out, (context->lastSample[0])>>8); |
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176 | } else |
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177 | bytestream_put_le16(&out, context->lastSample[0]); |
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178 | |||
179 | /* Write the actual samples */ |
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180 | for (i = 0; i < data_size; i++) |
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181 | *out++ = dpcm_predict(&context->lastSample[i & 1], *in++); |
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182 | |||
183 | avpkt->pts = context->input_frames <= 7 ? context->first_pts : frame->pts; |
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184 | avpkt->duration = data_size / avctx->channels; |
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185 | |||
186 | context->input_frames++; |
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187 | if (!in) |
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188 | context->input_frames = FFMAX(context->input_frames, 8); |
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189 | |||
190 | *got_packet_ptr = 1; |
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191 | return 0; |
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192 | } |
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193 | |||
194 | AVCodec ff_roq_dpcm_encoder = { |
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195 | .name = "roq_dpcm", |
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196 | .long_name = NULL_IF_CONFIG_SMALL("id RoQ DPCM"), |
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197 | .type = AVMEDIA_TYPE_AUDIO, |
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198 | .id = AV_CODEC_ID_ROQ_DPCM, |
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199 | .priv_data_size = sizeof(ROQDPCMContext), |
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200 | .init = roq_dpcm_encode_init, |
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201 | .encode2 = roq_dpcm_encode_frame, |
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202 | .close = roq_dpcm_encode_close, |
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203 | .capabilities = CODEC_CAP_DELAY, |
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204 | .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16, |
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205 | AV_SAMPLE_FMT_NONE }, |
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206 | };=>>>>>>><>>0; |