3 * Copyright (C) 2008 Jaikrishnan Menon
5 * This file is part of Libav.
7 * Libav 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.
12 * Libav 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * @author Jaikrishnan Menon
27 * supports: fibonacci delta encoding
28 * : exponential encoding
33 #include "libavutil/common.h"
35 /** decoder context */
36 typedef struct EightSvxContext {
41 /* buffer used to store the whole first packet.
42 data is only sent as one large packet */
48 static const int8_t fibonacci[16] = { -34, -21, -13, -8, -5, -3, -2, -1,
49 0, 1, 2, 3, 5, 8, 13, 21 };
50 static const int8_t exponential[16] = { -128, -64, -32, -16, -8, -4, -2, -1,
51 0, 1, 2, 4, 8, 16, 32, 64 };
53 #define MAX_FRAME_SIZE 32768
56 * Delta decode the compressed values in src, and put the resulting
57 * decoded samples in dst.
59 * @param[in,out] state starting value. it is saved for use in the next call.
61 static void delta_decode(uint8_t *dst, const uint8_t *src, int src_size,
62 uint8_t *state, const int8_t *table)
68 val = av_clip_uint8(val + table[d & 0xF]);
70 val = av_clip_uint8(val + table[d >> 4]);
77 static void raw_decode(uint8_t *dst, const int8_t *src, int src_size)
80 *dst++ = *src++ + 128;
84 static int eightsvx_decode_frame(AVCodecContext *avctx, void *data,
85 int *got_frame_ptr, AVPacket *avpkt)
87 EightSvxContext *esc = avctx->priv_data;
90 int is_compr = (avctx->codec_id != AV_CODEC_ID_PCM_S8_PLANAR);
92 /* for the first packet, copy data to buffer */
94 int hdr_size = is_compr ? 2 : 0;
95 int chan_size = (avpkt->size - hdr_size * avctx->channels) / avctx->channels;
97 if (avpkt->size < hdr_size * avctx->channels) {
98 av_log(avctx, AV_LOG_ERROR, "packet size is too small\n");
99 return AVERROR(EINVAL);
102 av_log(avctx, AV_LOG_ERROR, "unexpected data after first packet\n");
103 return AVERROR(EINVAL);
107 esc->fib_acc[0] = avpkt->data[1] + 128;
108 if (avctx->channels == 2)
109 esc->fib_acc[1] = avpkt->data[2+chan_size+1] + 128;
113 esc->data_size = chan_size;
114 if (!(esc->data[0] = av_malloc(chan_size)))
115 return AVERROR(ENOMEM);
116 if (avctx->channels == 2) {
117 if (!(esc->data[1] = av_malloc(chan_size))) {
118 av_freep(&esc->data[0]);
119 return AVERROR(ENOMEM);
122 memcpy(esc->data[0], &avpkt->data[hdr_size], chan_size);
123 if (avctx->channels == 2)
124 memcpy(esc->data[1], &avpkt->data[2*hdr_size+chan_size], chan_size);
127 av_log(avctx, AV_LOG_ERROR, "unexpected empty packet\n");
128 return AVERROR(EINVAL);
131 /* decode next piece of data from the buffer */
132 buf_size = FFMIN(MAX_FRAME_SIZE, esc->data_size - esc->data_idx);
138 /* get output buffer */
139 esc->frame.nb_samples = buf_size * (is_compr + 1);
140 if ((ret = ff_get_buffer(avctx, &esc->frame)) < 0) {
141 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
145 for (ch = 0; ch < avctx->channels; ch++) {
147 delta_decode(esc->frame.data[ch], &esc->data[ch][esc->data_idx],
148 buf_size, &esc->fib_acc[ch], esc->table);
150 raw_decode(esc->frame.data[ch], &esc->data[ch][esc->data_idx],
155 esc->data_idx += buf_size;
158 *(AVFrame *)data = esc->frame;
163 /** initialize 8svx decoder */
164 static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
166 EightSvxContext *esc = avctx->priv_data;
168 if (avctx->channels < 1 || avctx->channels > 2) {
169 av_log(avctx, AV_LOG_ERROR, "8SVX does not support more than 2 channels\n");
170 return AVERROR(EINVAL);
173 switch(avctx->codec->id) {
174 case AV_CODEC_ID_8SVX_FIB:
175 esc->table = fibonacci;
177 case AV_CODEC_ID_8SVX_EXP:
178 esc->table = exponential;
180 case AV_CODEC_ID_PCM_S8_PLANAR:
185 avctx->sample_fmt = AV_SAMPLE_FMT_U8P;
187 avcodec_get_frame_defaults(&esc->frame);
188 avctx->coded_frame = &esc->frame;
193 static av_cold int eightsvx_decode_close(AVCodecContext *avctx)
195 EightSvxContext *esc = avctx->priv_data;
197 av_freep(&esc->data[0]);
198 av_freep(&esc->data[1]);
203 AVCodec ff_eightsvx_fib_decoder = {
205 .type = AVMEDIA_TYPE_AUDIO,
206 .id = AV_CODEC_ID_8SVX_FIB,
207 .priv_data_size = sizeof (EightSvxContext),
208 .init = eightsvx_decode_init,
209 .close = eightsvx_decode_close,
210 .decode = eightsvx_decode_frame,
211 .capabilities = CODEC_CAP_DELAY | CODEC_CAP_DR1,
212 .long_name = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
213 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
214 AV_SAMPLE_FMT_NONE },
217 AVCodec ff_eightsvx_exp_decoder = {
219 .type = AVMEDIA_TYPE_AUDIO,
220 .id = AV_CODEC_ID_8SVX_EXP,
221 .priv_data_size = sizeof (EightSvxContext),
222 .init = eightsvx_decode_init,
223 .close = eightsvx_decode_close,
224 .decode = eightsvx_decode_frame,
225 .capabilities = CODEC_CAP_DELAY | CODEC_CAP_DR1,
226 .long_name = NULL_IF_CONFIG_SMALL("8SVX exponential"),
227 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
228 AV_SAMPLE_FMT_NONE },
231 AVCodec ff_pcm_s8_planar_decoder = {
232 .name = "pcm_s8_planar",
233 .type = AVMEDIA_TYPE_AUDIO,
234 .id = AV_CODEC_ID_PCM_S8_PLANAR,
235 .priv_data_size = sizeof(EightSvxContext),
236 .init = eightsvx_decode_init,
237 .close = eightsvx_decode_close,
238 .decode = eightsvx_decode_frame,
239 .capabilities = CODEC_CAP_DELAY | CODEC_CAP_DR1,
240 .long_name = NULL_IF_CONFIG_SMALL("PCM signed 8-bit planar"),
241 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
242 AV_SAMPLE_FMT_NONE },