2 * RealAudio Lossless decoder
4 * Copyright (c) 2012 Konstantin Shishkov
6 * This file is part of Libav.
8 * Libav is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * Libav is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * This is a decoder for Real Audio Lossless format.
26 * Dedicated to the mastermind behind it, Ralph Wiggum.
29 #include "libavutil/channel_layout.h"
38 #define FILTER_RAW 642
40 typedef struct VLCSet {
44 VLC filter_coeffs[10][11];
49 #define RALF_MAX_PKT_SIZE 8192
51 typedef struct RALFContext {
57 int32_t channel_data[2][4096];
59 int filter_params; ///< combined filter parameters for the current channel data
60 int filter_length; ///< length of the filter for the current channel data
61 int filter_bits; ///< filter precision for the current channel data
64 int bias[2]; ///< a constant value added to channel data after filtering
66 int num_blocks; ///< number of blocks inside the frame
68 int block_size[1 << 12]; ///< size of the blocks
69 int block_pts[1 << 12]; ///< block start time (in milliseconds)
75 #define MAX_ELEMS 644 // no RALF table uses more than that
77 static int init_ralf_vlc(VLC *vlc, const uint8_t *data, int elems)
79 uint8_t lens[MAX_ELEMS];
80 uint16_t codes[MAX_ELEMS];
81 int counts[17], prefixes[18];
86 for (i = 0; i <= 16; i++)
88 for (i = 0; i < elems; i++) {
89 cur_len = (nb ? *data & 0xF : *data >> 4) + 1;
91 max_bits = FFMAX(max_bits, cur_len);
97 for (i = 1; i <= 16; i++)
98 prefixes[i + 1] = (prefixes[i] + counts[i]) << 1;
100 for (i = 0; i < elems; i++)
101 codes[i] = prefixes[lens[i]]++;
103 return ff_init_vlc_sparse(vlc, FFMIN(max_bits, 9), elems,
104 lens, 1, 1, codes, 2, 2, NULL, 0, 0, 0);
107 static av_cold int decode_close(AVCodecContext *avctx)
109 RALFContext *ctx = avctx->priv_data;
112 for (i = 0; i < 3; i++) {
113 ff_free_vlc(&ctx->sets[i].filter_params);
114 ff_free_vlc(&ctx->sets[i].bias);
115 ff_free_vlc(&ctx->sets[i].coding_mode);
116 for (j = 0; j < 10; j++)
117 for (k = 0; k < 11; k++)
118 ff_free_vlc(&ctx->sets[i].filter_coeffs[j][k]);
119 for (j = 0; j < 15; j++)
120 ff_free_vlc(&ctx->sets[i].short_codes[j]);
121 for (j = 0; j < 125; j++)
122 ff_free_vlc(&ctx->sets[i].long_codes[j]);
128 static av_cold int decode_init(AVCodecContext *avctx)
130 RALFContext *ctx = avctx->priv_data;
134 if (avctx->extradata_size < 24 || memcmp(avctx->extradata, "LSD:", 4)) {
135 av_log(avctx, AV_LOG_ERROR, "Extradata is not groovy, dude\n");
136 return AVERROR_INVALIDDATA;
139 ctx->version = AV_RB16(avctx->extradata + 4);
140 if (ctx->version != 0x103) {
141 av_log_ask_for_sample(avctx, "unknown version %X\n", ctx->version);
142 return AVERROR_PATCHWELCOME;
145 avctx->channels = AV_RB16(avctx->extradata + 8);
146 avctx->sample_rate = AV_RB32(avctx->extradata + 12);
147 if (avctx->channels < 1 || avctx->channels > 2
148 || avctx->sample_rate < 8000 || avctx->sample_rate > 96000) {
149 av_log(avctx, AV_LOG_ERROR, "Invalid coding parameters %d Hz %d ch\n",
150 avctx->sample_rate, avctx->channels);
151 return AVERROR_INVALIDDATA;
153 avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
154 avctx->channel_layout = (avctx->channels == 2) ? AV_CH_LAYOUT_STEREO
157 avcodec_get_frame_defaults(&ctx->frame);
158 avctx->coded_frame = &ctx->frame;
160 ctx->max_frame_size = AV_RB32(avctx->extradata + 16);
161 if (ctx->max_frame_size > (1 << 20) || !ctx->max_frame_size) {
162 av_log(avctx, AV_LOG_ERROR, "invalid frame size %d\n",
163 ctx->max_frame_size);
165 ctx->max_frame_size = FFMAX(ctx->max_frame_size, avctx->sample_rate);
167 for (i = 0; i < 3; i++) {
168 ret = init_ralf_vlc(&ctx->sets[i].filter_params, filter_param_def[i],
169 FILTERPARAM_ELEMENTS);
174 ret = init_ralf_vlc(&ctx->sets[i].bias, bias_def[i], BIAS_ELEMENTS);
179 ret = init_ralf_vlc(&ctx->sets[i].coding_mode, coding_mode_def[i],
180 CODING_MODE_ELEMENTS);
185 for (j = 0; j < 10; j++) {
186 for (k = 0; k < 11; k++) {
187 ret = init_ralf_vlc(&ctx->sets[i].filter_coeffs[j][k],
188 filter_coeffs_def[i][j][k],
189 FILTER_COEFFS_ELEMENTS);
196 for (j = 0; j < 15; j++) {
197 ret = init_ralf_vlc(&ctx->sets[i].short_codes[j],
198 short_codes_def[i][j], SHORT_CODES_ELEMENTS);
204 for (j = 0; j < 125; j++) {
205 ret = init_ralf_vlc(&ctx->sets[i].long_codes[j],
206 long_codes_def[i][j], LONG_CODES_ELEMENTS);
217 static inline int extend_code(GetBitContext *gb, int val, int range, int bits)
220 val = -range - get_ue_golomb(gb);
221 } else if (val == range * 2) {
222 val = range + get_ue_golomb(gb);
227 val = (val << bits) | get_bits(gb, bits);
231 static int decode_channel(RALFContext *ctx, GetBitContext *gb, int ch,
232 int length, int mode, int bits)
236 VLCSet *set = ctx->sets + mode;
237 VLC *code_vlc; int range, range2, add_bits;
238 int *dst = ctx->channel_data[ch];
240 ctx->filter_params = get_vlc2(gb, set->filter_params.table, 9, 2);
241 ctx->filter_bits = (ctx->filter_params - 2) >> 6;
242 ctx->filter_length = ctx->filter_params - (ctx->filter_bits << 6) - 1;
244 if (ctx->filter_params == FILTER_RAW) {
245 for (i = 0; i < length; i++)
246 dst[i] = get_bits(gb, bits);
251 ctx->bias[ch] = get_vlc2(gb, set->bias.table, 9, 2);
252 ctx->bias[ch] = extend_code(gb, ctx->bias[ch], 127, 4);
254 if (ctx->filter_params == FILTER_NONE) {
255 memset(dst, 0, sizeof(*dst) * length);
259 if (ctx->filter_params > 1) {
260 int cmode = 0, coeff = 0;
261 VLC *vlc = set->filter_coeffs[ctx->filter_bits] + 5;
263 add_bits = ctx->filter_bits;
265 for (i = 0; i < ctx->filter_length; i++) {
266 t = get_vlc2(gb, vlc[cmode].table, vlc[cmode].bits, 2);
267 t = extend_code(gb, t, 21, add_bits);
269 coeff -= 12 << add_bits;
271 ctx->filter[i] = coeff;
273 cmode = coeff >> add_bits;
275 cmode = -1 - av_log2(-cmode);
278 } else if (cmode > 0) {
279 cmode = 1 + av_log2(cmode);
286 code_params = get_vlc2(gb, set->coding_mode.table, set->coding_mode.bits, 2);
287 if (code_params >= 15) {
288 add_bits = av_clip((code_params / 5 - 3) / 2, 0, 10);
289 if (add_bits > 9 && (code_params % 5) != 2)
293 code_vlc = set->long_codes + code_params - 15;
298 code_vlc = set->short_codes + code_params;
301 for (i = 0; i < length; i += 2) {
304 t = get_vlc2(gb, code_vlc->table, code_vlc->bits, 2);
307 dst[i] = extend_code(gb, code1, range, 0) << add_bits;
308 dst[i + 1] = extend_code(gb, code2, range, 0) << add_bits;
310 dst[i] |= get_bits(gb, add_bits);
311 dst[i + 1] |= get_bits(gb, add_bits);
318 static void apply_lpc(RALFContext *ctx, int ch, int length, int bits)
321 int *audio = ctx->channel_data[ch];
322 int bias = 1 << (ctx->filter_bits - 1);
323 int max_clip = (1 << bits) - 1, min_clip = -max_clip - 1;
325 for (i = 1; i < length; i++) {
326 int flen = FFMIN(ctx->filter_length, i);
329 for (j = 0; j < flen; j++)
330 acc += ctx->filter[j] * audio[i - j - 1];
332 acc = (acc + bias - 1) >> ctx->filter_bits;
333 acc = FFMAX(acc, min_clip);
335 acc = (acc + bias) >> ctx->filter_bits;
336 acc = FFMIN(acc, max_clip);
342 static int decode_block(AVCodecContext *avctx, GetBitContext *gb,
343 int16_t *dst0, int16_t *dst1)
345 RALFContext *ctx = avctx->priv_data;
347 int dmode, mode[2], bits[2];
351 len = 12 - get_unary(gb, 0, 6);
353 if (len <= 7) len ^= 1; // codes for length = 6 and 7 are swapped
356 if (ctx->sample_offset + len > ctx->max_frame_size) {
357 av_log(avctx, AV_LOG_ERROR,
358 "Decoder's stomach is crying, it ate too many samples\n");
359 return AVERROR_INVALIDDATA;
362 if (avctx->channels > 1)
363 dmode = get_bits(gb, 2) + 1;
367 mode[0] = (dmode == 4) ? 1 : 0;
368 mode[1] = (dmode >= 2) ? 2 : 0;
370 bits[1] = (mode[1] == 2) ? 17 : 16;
372 for (ch = 0; ch < avctx->channels; ch++) {
373 if ((ret = decode_channel(ctx, gb, ch, len, mode[ch], bits[ch])) < 0)
375 if (ctx->filter_params > 1 && ctx->filter_params != FILTER_RAW) {
376 ctx->filter_bits += 3;
377 apply_lpc(ctx, ch, len, bits[ch]);
379 if (get_bits_left(gb) < 0)
380 return AVERROR_INVALIDDATA;
382 ch0 = ctx->channel_data[0];
383 ch1 = ctx->channel_data[1];
386 for (i = 0; i < len; i++)
387 dst0[i] = ch0[i] + ctx->bias[0];
390 for (i = 0; i < len; i++) {
391 dst0[i] = ch0[i] + ctx->bias[0];
392 dst1[i] = ch1[i] + ctx->bias[1];
396 for (i = 0; i < len; i++) {
397 ch0[i] += ctx->bias[0];
399 dst1[i] = ch0[i] - (ch1[i] + ctx->bias[1]);
403 for (i = 0; i < len; i++) {
404 t = ch0[i] + ctx->bias[0];
405 t2 = ch1[i] + ctx->bias[1];
411 for (i = 0; i < len; i++) {
412 t = ch1[i] + ctx->bias[1];
413 t2 = ((ch0[i] + ctx->bias[0]) << 1) | (t & 1);
414 dst0[i] = (t2 + t) / 2;
415 dst1[i] = (t2 - t) / 2;
420 ctx->sample_offset += len;
425 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,
428 RALFContext *ctx = avctx->priv_data;
433 int table_size, table_bytes, i;
434 const uint8_t *src, *block_pointer;
440 table_bytes = (AV_RB16(avpkt->data) + 7) >> 3;
441 if (table_bytes + 3 > avpkt->size || avpkt->size > RALF_MAX_PKT_SIZE) {
442 av_log(avctx, AV_LOG_ERROR, "Wrong packet's breath smells of wrong data!\n");
443 return AVERROR_INVALIDDATA;
445 if (memcmp(ctx->pkt, avpkt->data, 2 + table_bytes)) {
446 av_log(avctx, AV_LOG_ERROR, "Wrong packet tails are wrong!\n");
447 return AVERROR_INVALIDDATA;
451 src_size = RALF_MAX_PKT_SIZE + avpkt->size;
452 memcpy(ctx->pkt + RALF_MAX_PKT_SIZE, avpkt->data + 2 + table_bytes,
453 avpkt->size - 2 - table_bytes);
455 if (avpkt->size == RALF_MAX_PKT_SIZE) {
456 memcpy(ctx->pkt, avpkt->data, avpkt->size);
463 src_size = avpkt->size;
466 ctx->frame.nb_samples = ctx->max_frame_size;
467 if ((ret = ff_get_buffer(avctx, &ctx->frame)) < 0) {
468 av_log(avctx, AV_LOG_ERROR, "Me fail get_buffer()? That's unpossible!\n");
471 samples0 = (int16_t *)ctx->frame.data[0];
472 samples1 = (int16_t *)ctx->frame.data[1];
475 av_log(avctx, AV_LOG_ERROR, "too short packets are too short!\n");
476 return AVERROR_INVALIDDATA;
478 table_size = AV_RB16(src);
479 table_bytes = (table_size + 7) >> 3;
480 if (src_size < table_bytes + 3) {
481 av_log(avctx, AV_LOG_ERROR, "short packets are short!\n");
482 return AVERROR_INVALIDDATA;
484 init_get_bits(&gb, src + 2, table_size);
486 while (get_bits_left(&gb) > 0) {
487 ctx->block_size[ctx->num_blocks] = get_bits(&gb, 15);
488 if (get_bits1(&gb)) {
489 ctx->block_pts[ctx->num_blocks] = get_bits(&gb, 9);
491 ctx->block_pts[ctx->num_blocks] = 0;
496 block_pointer = src + table_bytes + 2;
497 bytes_left = src_size - table_bytes - 2;
498 ctx->sample_offset = 0;
499 for (i = 0; i < ctx->num_blocks; i++) {
500 if (bytes_left < ctx->block_size[i]) {
501 av_log(avctx, AV_LOG_ERROR, "I'm pedaling backwards\n");
504 init_get_bits(&gb, block_pointer, ctx->block_size[i] * 8);
505 if (decode_block(avctx, &gb, samples0 + ctx->sample_offset,
506 samples1 + ctx->sample_offset) < 0) {
507 av_log(avctx, AV_LOG_ERROR, "Sir, I got carsick in your office. Not decoding the rest of packet.\n");
510 block_pointer += ctx->block_size[i];
511 bytes_left -= ctx->block_size[i];
514 ctx->frame.nb_samples = ctx->sample_offset;
515 *got_frame_ptr = ctx->sample_offset > 0;
516 *(AVFrame*)data = ctx->frame;
521 static void decode_flush(AVCodecContext *avctx)
523 RALFContext *ctx = avctx->priv_data;
529 AVCodec ff_ralf_decoder = {
531 .type = AVMEDIA_TYPE_AUDIO,
532 .id = AV_CODEC_ID_RALF,
533 .priv_data_size = sizeof(RALFContext),
535 .close = decode_close,
536 .decode = decode_frame,
537 .flush = decode_flush,
538 .capabilities = CODEC_CAP_DR1,
539 .long_name = NULL_IF_CONFIG_SMALL("RealAudio Lossless"),
540 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
541 AV_SAMPLE_FMT_NONE },