yading@10: /*
yading@10:  * Aura 2 decoder
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Aura 2 decoder
yading@10:  */
yading@10: 
yading@10: #include "avcodec.h"
yading@10: #include "internal.h"
yading@10: #include "libavutil/internal.h"
yading@10: 
yading@10: static av_cold int aura_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     /* width needs to be divisible by 4 for this codec to work */
yading@10:     if (avctx->width & 0x3)
yading@10:         return AVERROR(EINVAL);
yading@10:     avctx->pix_fmt = AV_PIX_FMT_YUV422P;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int aura_decode_frame(AVCodecContext *avctx,
yading@10:                              void *data, int *got_frame,
yading@10:                              AVPacket *pkt)
yading@10: {
yading@10:     AVFrame *frame = data;
yading@10:     uint8_t *Y, *U, *V;
yading@10:     uint8_t val;
yading@10:     int x, y, ret;
yading@10:     const uint8_t *buf = pkt->data;
yading@10: 
yading@10:     /* prediction error tables (make it clear that they are signed values) */
yading@10:     const int8_t *delta_table = (const int8_t*)buf + 16;
yading@10: 
yading@10:     if (pkt->size != 48 + avctx->height * avctx->width) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
yading@10:                pkt->size, 48 + avctx->height * avctx->width);
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     /* pixel data starts 48 bytes in, after 3x16-byte tables */
yading@10:     buf += 48;
yading@10: 
yading@10:     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     Y = frame->data[0];
yading@10:     U = frame->data[1];
yading@10:     V = frame->data[2];
yading@10: 
yading@10:     /* iterate through each line in the height */
yading@10:     for (y = 0; y < avctx->height; y++) {
yading@10:         /* reset predictors */
yading@10:         val  = *buf++;
yading@10:         U[0] = val & 0xF0;
yading@10:         Y[0] = val << 4;
yading@10:         val  = *buf++;
yading@10:         V[0] = val & 0xF0;
yading@10:         Y[1] = Y[0] + delta_table[val & 0xF];
yading@10:         Y   += 2; U++; V++;
yading@10: 
yading@10:         /* iterate through the remaining pixel groups (4 pixels/group) */
yading@10:         for (x = 1; x < (avctx->width >> 1); x++) {
yading@10:             val  = *buf++;
yading@10:             U[0] = U[-1] + delta_table[val >> 4];
yading@10:             Y[0] = Y[-1] + delta_table[val & 0xF];
yading@10:             val  = *buf++;
yading@10:             V[0] = V[-1] + delta_table[val >> 4];
yading@10:             Y[1] = Y[ 0] + delta_table[val & 0xF];
yading@10:             Y   += 2; U++; V++;
yading@10:         }
yading@10:         Y += frame->linesize[0] -  avctx->width;
yading@10:         U += frame->linesize[1] - (avctx->width >> 1);
yading@10:         V += frame->linesize[2] - (avctx->width >> 1);
yading@10:     }
yading@10: 
yading@10:     *got_frame = 1;
yading@10: 
yading@10:     return pkt->size;
yading@10: }
yading@10: 
yading@10: AVCodec ff_aura2_decoder = {
yading@10:     .name           = "aura2",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_AURA2,
yading@10:     .init           = aura_decode_init,
yading@10:     .decode         = aura_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Auravision Aura 2"),
yading@10: };