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/* |
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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 FFmpeg. |
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* |
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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/channel_layout.h" |
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#include "libavutil/common.h" |
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#include "libavutil/intreadwrite.h" |
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#include "avcodec.h" |
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#include "internal.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_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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}; |
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static av_cold int ws_snd_decode_init(AVCodecContext *avctx) |
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{ |
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avctx->channels = 1; |
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avctx->channel_layout = AV_CH_LAYOUT_MONO; |
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avctx->sample_fmt = AV_SAMPLE_FMT_U8; |
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return 0; |
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} |
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static int ws_snd_decode_frame(AVCodecContext *avctx, void *data, |
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int *got_frame_ptr, AVPacket *avpkt) |
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{ |
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AVFrame *frame = data; |
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const uint8_t *buf = avpkt->data; |
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int buf_size = avpkt->size; |
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int in_size, out_size, ret; |
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int sample = 128; |
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uint8_t *samples; |
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uint8_t *samples_end; |
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✗✓ |
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if (!buf_size) |
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return 0; |
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✗✓ |
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if (buf_size < 4) { |
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av_log(avctx, AV_LOG_ERROR, "packet is too small\n"); |
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return AVERROR(EINVAL); |
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} |
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out_size = AV_RL16(&buf[0]); |
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in_size = AV_RL16(&buf[2]); |
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buf += 4; |
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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 AVERROR_INVALIDDATA; |
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} |
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/* get output buffer */ |
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frame->nb_samples = out_size; |
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✗✓ |
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
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return ret; |
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samples = frame->data[0]; |
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samples_end = samples + out_size; |
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✗✓ |
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if (in_size == out_size) { |
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memcpy(samples, buf, out_size); |
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*got_frame_ptr = 1; |
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return buf_size; |
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} |
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✓✓✓✗
|
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while (samples < samples_end && buf - avpkt->data < buf_size) { |
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int code, smp, size; |
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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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/* make sure we don't write past the output buffer */ |
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✓✓✓✓
|
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switch (code) { |
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case 0: smp = 4 * (count + 1); break; |
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case 1: smp = 2 * (count + 1); break; |
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✓✓ |
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case 2: smp = (count & 0x20) ? 1 : count + 1; break; |
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default: smp = count + 1; break; |
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} |
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✗✓ |
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if (samples_end - samples < smp) |
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break; |
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/* make sure we don't read past the input buffer */ |
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✓✓✓✓ ✓✓ |
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size = ((code == 2 && (count & 0x20)) || code == 3) ? 0 : count + 1; |
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✗✓ |
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if ((buf - avpkt->data) + size > buf_size) |
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break; |
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✓✓✓✓
|
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switch (code) { |
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case 0: /* ADPCM 2-bit */ |
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✓✓ |
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for (count++; count > 0; count--) { |
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code = *buf++; |
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sample += ( code & 0x3) - 2; |
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sample = av_clip_uint8(sample); |
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*samples++ = sample; |
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sample += ((code >> 2) & 0x3) - 2; |
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sample = av_clip_uint8(sample); |
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*samples++ = sample; |
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sample += ((code >> 4) & 0x3) - 2; |
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sample = av_clip_uint8(sample); |
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*samples++ = sample; |
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sample += (code >> 6) - 2; |
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sample = av_clip_uint8(sample); |
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*samples++ = sample; |
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} |
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break; |
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case 1: /* ADPCM 4-bit */ |
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✓✓ |
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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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sample = av_clip_uint8(sample); |
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*samples++ = sample; |
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sample += ws_adpcm_4bit[code >> 4]; |
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sample = av_clip_uint8(sample); |
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*samples++ = sample; |
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} |
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break; |
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case 2: /* no compression */ |
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✓✓ |
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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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sample = av_clip_uint8(sample); |
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*samples++ = sample; |
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} else { /* copy */ |
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memcpy(samples, buf, smp); |
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samples += smp; |
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buf += smp; |
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sample = buf[-1]; |
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} |
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break; |
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default: /* run */ |
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memset(samples, sample, smp); |
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samples += smp; |
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} |
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} |
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frame->nb_samples = samples - frame->data[0]; |
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*got_frame_ptr = 1; |
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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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.long_name = NULL_IF_CONFIG_SMALL("Westwood Audio (SND1)"), |
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.type = AVMEDIA_TYPE_AUDIO, |
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.id = AV_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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.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF, |
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.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, |
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}; |