forked from KolibriOS/kolibrios
109 lines
3.2 KiB
C
109 lines
3.2 KiB
C
/*
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* Aura 2 decoder
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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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/**
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* @file
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* Aura 2 decoder
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*/
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#include "avcodec.h"
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#include "internal.h"
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#include "libavutil/internal.h"
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static av_cold int aura_decode_init(AVCodecContext *avctx)
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{
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/* width needs to be divisible by 4 for this codec to work */
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if (avctx->width & 0x3)
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return AVERROR(EINVAL);
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avctx->pix_fmt = AV_PIX_FMT_YUV422P;
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return 0;
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}
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static int aura_decode_frame(AVCodecContext *avctx,
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void *data, int *got_frame,
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AVPacket *pkt)
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{
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AVFrame *frame = data;
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uint8_t *Y, *U, *V;
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uint8_t val;
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int x, y, ret;
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const uint8_t *buf = pkt->data;
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/* prediction error tables (make it clear that they are signed values) */
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const int8_t *delta_table = (const int8_t*)buf + 16;
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if (pkt->size != 48 + avctx->height * avctx->width) {
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av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
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pkt->size, 48 + avctx->height * avctx->width);
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return AVERROR_INVALIDDATA;
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}
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/* pixel data starts 48 bytes in, after 3x16-byte tables */
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buf += 48;
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
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return ret;
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Y = frame->data[0];
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U = frame->data[1];
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V = frame->data[2];
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/* iterate through each line in the height */
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for (y = 0; y < avctx->height; y++) {
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/* reset predictors */
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val = *buf++;
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U[0] = val & 0xF0;
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Y[0] = val << 4;
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val = *buf++;
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V[0] = val & 0xF0;
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Y[1] = Y[0] + delta_table[val & 0xF];
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Y += 2; U++; V++;
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/* iterate through the remaining pixel groups (4 pixels/group) */
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for (x = 1; x < (avctx->width >> 1); x++) {
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val = *buf++;
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U[0] = U[-1] + delta_table[val >> 4];
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Y[0] = Y[-1] + delta_table[val & 0xF];
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val = *buf++;
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V[0] = V[-1] + delta_table[val >> 4];
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Y[1] = Y[ 0] + delta_table[val & 0xF];
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Y += 2; U++; V++;
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}
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Y += frame->linesize[0] - avctx->width;
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U += frame->linesize[1] - (avctx->width >> 1);
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V += frame->linesize[2] - (avctx->width >> 1);
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}
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*got_frame = 1;
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return pkt->size;
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}
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AVCodec ff_aura2_decoder = {
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.name = "aura2",
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.long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"),
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.type = AVMEDIA_TYPE_VIDEO,
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.id = AV_CODEC_ID_AURA2,
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.init = aura_decode_init,
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.decode = aura_decode_frame,
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.capabilities = CODEC_CAP_DR1,
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};
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