1/* 2 * Aura 2 decoder 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21/** 22 * @file 23 * Aura 2 decoder 24 */ 25 26#include "avcodec.h" 27#include "internal.h" 28#include "libavutil/internal.h" 29 30static av_cold int aura_decode_init(AVCodecContext *avctx) 31{ 32 /* width needs to be divisible by 4 for this codec to work */ 33 if (avctx->width & 0x3) 34 return AVERROR(EINVAL); 35 avctx->pix_fmt = AV_PIX_FMT_YUV422P; 36 37 return 0; 38} 39 40static int aura_decode_frame(AVCodecContext *avctx, 41 void *data, int *got_frame, 42 AVPacket *pkt) 43{ 44 AVFrame *frame = data; 45 uint8_t *Y, *U, *V; 46 uint8_t val; 47 int x, y, ret; 48 const uint8_t *buf = pkt->data; 49 50 /* prediction error tables (make it clear that they are signed values) */ 51 const int8_t *delta_table = (const int8_t*)buf + 16; 52 53 if (pkt->size != 48 + avctx->height * avctx->width) { 54 av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n", 55 pkt->size, 48 + avctx->height * avctx->width); 56 return AVERROR_INVALIDDATA; 57 } 58 59 /* pixel data starts 48 bytes in, after 3x16-byte tables */ 60 buf += 48; 61 62 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) 63 return ret; 64 65 Y = frame->data[0]; 66 U = frame->data[1]; 67 V = frame->data[2]; 68 69 /* iterate through each line in the height */ 70 for (y = 0; y < avctx->height; y++) { 71 /* reset predictors */ 72 val = *buf++; 73 U[0] = val & 0xF0; 74 Y[0] = val << 4; 75 val = *buf++; 76 V[0] = val & 0xF0; 77 Y[1] = Y[0] + delta_table[val & 0xF]; 78 Y += 2; U++; V++; 79 80 /* iterate through the remaining pixel groups (4 pixels/group) */ 81 for (x = 1; x < (avctx->width >> 1); x++) { 82 val = *buf++; 83 U[0] = U[-1] + delta_table[val >> 4]; 84 Y[0] = Y[-1] + delta_table[val & 0xF]; 85 val = *buf++; 86 V[0] = V[-1] + delta_table[val >> 4]; 87 Y[1] = Y[ 0] + delta_table[val & 0xF]; 88 Y += 2; U++; V++; 89 } 90 Y += frame->linesize[0] - avctx->width; 91 U += frame->linesize[1] - (avctx->width >> 1); 92 V += frame->linesize[2] - (avctx->width >> 1); 93 } 94 95 *got_frame = 1; 96 97 return pkt->size; 98} 99 100AVCodec ff_aura2_decoder = { 101 .name = "aura2", 102 .long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"), 103 .type = AVMEDIA_TYPE_VIDEO, 104 .id = AV_CODEC_ID_AURA2, 105 .init = aura_decode_init, 106 .decode = aura_decode_frame, 107 .capabilities = CODEC_CAP_DR1, 108}; 109