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 "codec_internal.h" 28#include "internal.h" 29#include "libavutil/internal.h" 30 31static av_cold int aura_decode_init(AVCodecContext *avctx) 32{ 33 /* width needs to be divisible by 4 for this codec to work */ 34 if (avctx->width & 0x3) 35 return AVERROR(EINVAL); 36 avctx->pix_fmt = AV_PIX_FMT_YUV422P; 37 38 return 0; 39} 40 41static int aura_decode_frame(AVCodecContext *avctx, AVFrame *frame, 42 int *got_frame, AVPacket *pkt) 43{ 44 uint8_t *Y, *U, *V; 45 uint8_t val; 46 int x, y, ret; 47 const uint8_t *buf = pkt->data; 48 49 /* prediction error tables (make it clear that they are signed values) */ 50 const int8_t *delta_table = (const int8_t*)buf + 16; 51 52 if (pkt->size != 48 + avctx->height * avctx->width) { 53 av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n", 54 pkt->size, 48 + avctx->height * avctx->width); 55 return AVERROR_INVALIDDATA; 56 } 57 58 /* pixel data starts 48 bytes in, after 3x16-byte tables */ 59 buf += 48; 60 61 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) 62 return ret; 63 64 Y = frame->data[0]; 65 U = frame->data[1]; 66 V = frame->data[2]; 67 68 /* iterate through each line in the height */ 69 for (y = 0; y < avctx->height; y++) { 70 /* reset predictors */ 71 val = *buf++; 72 U[0] = val & 0xF0; 73 Y[0] = val << 4; 74 val = *buf++; 75 V[0] = val & 0xF0; 76 Y[1] = Y[0] + delta_table[val & 0xF]; 77 Y += 2; U++; V++; 78 79 /* iterate through the remaining pixel groups (4 pixels/group) */ 80 for (x = 1; x < (avctx->width >> 1); x++) { 81 val = *buf++; 82 U[0] = U[-1] + delta_table[val >> 4]; 83 Y[0] = Y[-1] + delta_table[val & 0xF]; 84 val = *buf++; 85 V[0] = V[-1] + delta_table[val >> 4]; 86 Y[1] = Y[ 0] + delta_table[val & 0xF]; 87 Y += 2; U++; V++; 88 } 89 Y += frame->linesize[0] - avctx->width; 90 U += frame->linesize[1] - (avctx->width >> 1); 91 V += frame->linesize[2] - (avctx->width >> 1); 92 } 93 94 *got_frame = 1; 95 96 return pkt->size; 97} 98 99const FFCodec ff_aura2_decoder = { 100 .p.name = "aura2", 101 .p.long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"), 102 .p.type = AVMEDIA_TYPE_VIDEO, 103 .p.id = AV_CODEC_ID_AURA2, 104 .init = aura_decode_init, 105 FF_CODEC_DECODE_CB(aura_decode_frame), 106 .p.capabilities = AV_CODEC_CAP_DR1, 107 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, 108}; 109