| 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 | |
| 30 | static 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 | |
| 40 | static 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 | |
| 100 | AVCodec 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 | }; |