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156 lines
4.6 KiB
156 lines
4.6 KiB
/* |
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* Westwood SNDx codecs |
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* Copyright (c) 2005 Konstantin Shishkov |
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* |
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* This file is part of Libav. |
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* |
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* Libav is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* Libav is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with Libav; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include <stdint.h> |
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#include "libavutil/intreadwrite.h" |
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#include "avcodec.h" |
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/** |
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* @file |
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* Westwood SNDx codecs. |
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* |
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* Reference documents about VQA format and its audio codecs |
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* can be found here: |
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* http://www.multimedia.cx |
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*/ |
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static const int8_t ws_adpcm_2bit[] = { -2, -1, 0, 1}; |
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static const int8_t ws_adpcm_4bit[] = { |
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-9, -8, -6, -5, -4, -3, -2, -1, |
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0, 1, 2, 3, 4, 5, 6, 8 }; |
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#define CLIP8(a) if(a>127)a=127;if(a<-128)a=-128; |
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static av_cold int ws_snd_decode_init(AVCodecContext * avctx) |
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{ |
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// WSSNDContext *c = avctx->priv_data; |
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avctx->sample_fmt = AV_SAMPLE_FMT_S16; |
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return 0; |
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} |
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static int ws_snd_decode_frame(AVCodecContext *avctx, |
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void *data, int *data_size, |
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AVPacket *avpkt) |
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{ |
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const uint8_t *buf = avpkt->data; |
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int buf_size = avpkt->size; |
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// WSSNDContext *c = avctx->priv_data; |
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int in_size, out_size; |
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int sample = 0; |
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int i; |
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short *samples = data; |
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if (!buf_size) |
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return 0; |
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out_size = AV_RL16(&buf[0]); |
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*data_size = out_size * 2; |
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in_size = AV_RL16(&buf[2]); |
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buf += 4; |
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if (out_size > *data_size) { |
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av_log(avctx, AV_LOG_ERROR, "Frame is too large to fit in buffer\n"); |
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return -1; |
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} |
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if (in_size > buf_size) { |
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av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n"); |
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return -1; |
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} |
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if (in_size == out_size) { |
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for (i = 0; i < out_size; i++) |
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*samples++ = (*buf++ - 0x80) << 8; |
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return buf_size; |
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} |
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while (out_size > 0) { |
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int code; |
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uint8_t count; |
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code = (*buf) >> 6; |
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count = (*buf) & 0x3F; |
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buf++; |
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switch(code) { |
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case 0: /* ADPCM 2-bit */ |
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for (count++; count > 0; count--) { |
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code = *buf++; |
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sample += ws_adpcm_2bit[code & 0x3]; |
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CLIP8(sample); |
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*samples++ = sample << 8; |
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sample += ws_adpcm_2bit[(code >> 2) & 0x3]; |
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CLIP8(sample); |
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*samples++ = sample << 8; |
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sample += ws_adpcm_2bit[(code >> 4) & 0x3]; |
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CLIP8(sample); |
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*samples++ = sample << 8; |
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sample += ws_adpcm_2bit[(code >> 6) & 0x3]; |
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CLIP8(sample); |
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*samples++ = sample << 8; |
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out_size -= 4; |
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} |
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break; |
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case 1: /* ADPCM 4-bit */ |
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for (count++; count > 0; count--) { |
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code = *buf++; |
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sample += ws_adpcm_4bit[code & 0xF]; |
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CLIP8(sample); |
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*samples++ = sample << 8; |
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sample += ws_adpcm_4bit[code >> 4]; |
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CLIP8(sample); |
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*samples++ = sample << 8; |
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out_size -= 2; |
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} |
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break; |
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case 2: /* no compression */ |
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if (count & 0x20) { /* big delta */ |
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int8_t t; |
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t = count; |
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t <<= 3; |
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sample += t >> 3; |
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*samples++ = sample << 8; |
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out_size--; |
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} else { /* copy */ |
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for (count++; count > 0; count--) { |
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*samples++ = (*buf++ - 0x80) << 8; |
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out_size--; |
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} |
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sample = buf[-1] - 0x80; |
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} |
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break; |
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default: /* run */ |
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for(count++; count > 0; count--) { |
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*samples++ = sample << 8; |
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out_size--; |
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} |
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} |
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} |
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return buf_size; |
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} |
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AVCodec ff_ws_snd1_decoder = { |
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.name = "ws_snd1", |
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.type = AVMEDIA_TYPE_AUDIO, |
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.id = CODEC_ID_WESTWOOD_SND1, |
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.init = ws_snd_decode_init, |
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.decode = ws_snd_decode_frame, |
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.long_name = NULL_IF_CONFIG_SMALL("Westwood Audio (SND1)"), |
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};
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