1/* 2 * VBLE Decoder 3 * Copyright (c) 2011 Derek Buitenhuis 4 * 5 * This file is part of Libav. 6 * 7 * Libav is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * Libav is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with Libav; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22/** 23 * @file 24 * VBLE Decoder 25 */ 26 27#define BITSTREAM_READER_LE 28 29#include "avcodec.h" 30#include "dsputil.h" 31#include "get_bits.h" 32 33typedef struct { 34 AVCodecContext *avctx; 35 DSPContext dsp; 36 37 int size; 38 uint8_t *val; /* First holds the lengths of vlc symbols and then their values */ 39} VBLEContext; 40 41static uint8_t vble_read_reverse_unary(GetBitContext *gb) 42{ 43 /* At most we need to read 9 bits total to get indices up to 8 */ 44 uint8_t val = show_bits(gb, 8); 45 46 if (val) { 47 val = 7 - av_log2_16bit(av_reverse[val]); 48 skip_bits(gb, val + 1); 49 return val; 50 } else { 51 skip_bits(gb, 8); 52 if (get_bits1(gb)) 53 return 8; 54 } 55 56 /* Return something larger than 8 on error */ 57 return UINT8_MAX; 58} 59 60static int vble_unpack(VBLEContext *ctx, GetBitContext *gb) 61{ 62 int i; 63 64 /* Read all the lengths in first */ 65 for (i = 0; i < ctx->size; i++) { 66 ctx->val[i] = vble_read_reverse_unary(gb); 67 68 if (ctx->val[i] == UINT8_MAX) 69 return -1; 70 } 71 72 for (i = 0; i < ctx->size; i++) { 73 /* Check we have enough bits left */ 74 if (get_bits_left(gb) < ctx->val[i]) 75 return -1; 76 77 /* get_bits can't take a length of 0 */ 78 if (ctx->val[i]) 79 ctx->val[i] = (1 << ctx->val[i]) + get_bits(gb, ctx->val[i]) - 1; 80 } 81 82 return 0; 83} 84 85static void vble_restore_plane(VBLEContext *ctx, int plane, int offset, 86 int width, int height) 87{ 88 AVFrame *pic = ctx->avctx->coded_frame; 89 uint8_t *dst = pic->data[plane]; 90 uint8_t *val = ctx->val + offset; 91 int stride = pic->linesize[plane]; 92 int i, j, left, left_top; 93 94 for (i = 0; i < height; i++) { 95 for (j = 0; j < width; j++) 96 val[j] = (val[j] >> 1) ^ -(val[j] & 1); 97 98 if (i) { 99 left = 0; 100 left_top = dst[-stride]; 101 ctx->dsp.add_hfyu_median_prediction(dst, dst-stride, val, 102 width, &left, &left_top); 103 } else { 104 dst[0] = val[0]; 105 for (j = 1; j < width; j++) 106 dst[j] = val[j] + dst[j - 1]; 107 } 108 dst += stride; 109 val += width; 110 } 111} 112 113static int vble_decode_frame(AVCodecContext *avctx, void *data, int *data_size, 114 AVPacket *avpkt) 115{ 116 VBLEContext *ctx = avctx->priv_data; 117 AVFrame *pic = avctx->coded_frame; 118 GetBitContext gb; 119 const uint8_t *src = avpkt->data; 120 int version; 121 int offset = 0; 122 int width_uv = avctx->width / 2, height_uv = avctx->height / 2; 123 124 pic->reference = 0; 125 126 /* Clear buffer if need be */ 127 if (pic->data[0]) 128 avctx->release_buffer(avctx, pic); 129 130 /* Allocate buffer */ 131 if (avctx->get_buffer(avctx, pic) < 0) { 132 av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n"); 133 return AVERROR(ENOMEM); 134 } 135 136 /* Set flags */ 137 pic->key_frame = 1; 138 pic->pict_type = AV_PICTURE_TYPE_I; 139 140 /* Version should always be 1 */ 141 version = AV_RL32(src); 142 143 if (version != 1) { 144 av_log(avctx, AV_LOG_ERROR, "Unsupported VBLE Version: %d\n", version); 145 return AVERROR_INVALIDDATA; 146 } 147 148 init_get_bits(&gb, src + 4, (avpkt->size - 4) * 8); 149 150 /* Unpack */ 151 if (vble_unpack(ctx, &gb) < 0) { 152 av_log(avctx, AV_LOG_ERROR, "Invalid Code\n"); 153 return AVERROR_INVALIDDATA; 154 } 155 156 /* Restore planes. Should be almost identical to Huffyuv's. */ 157 vble_restore_plane(ctx, 0, offset, avctx->width, avctx->height); 158 159 /* Chroma */ 160 if (!(ctx->avctx->flags & CODEC_FLAG_GRAY)) { 161 offset += avctx->width * avctx->height; 162 vble_restore_plane(ctx, 1, offset, width_uv, height_uv); 163 164 offset += width_uv * height_uv; 165 vble_restore_plane(ctx, 2, offset, width_uv, height_uv); 166 } 167 168 *data_size = sizeof(AVFrame); 169 *(AVFrame *)data = *pic; 170 171 return avpkt->size; 172} 173 174static av_cold int vble_decode_close(AVCodecContext *avctx) 175{ 176 VBLEContext *ctx = avctx->priv_data; 177 AVFrame *pic = avctx->coded_frame; 178 179 if (pic->data[0]) 180 avctx->release_buffer(avctx, pic); 181 182 av_freep(&avctx->coded_frame); 183 av_freep(&ctx->val); 184 185 return 0; 186} 187 188static av_cold int vble_decode_init(AVCodecContext *avctx) 189{ 190 VBLEContext *ctx = avctx->priv_data; 191 192 /* Stash for later use */ 193 ctx->avctx = avctx; 194 dsputil_init(&ctx->dsp, avctx); 195 196 avctx->pix_fmt = PIX_FMT_YUV420P; 197 avctx->bits_per_raw_sample = 8; 198 avctx->coded_frame = avcodec_alloc_frame(); 199 200 if (!avctx->coded_frame) { 201 av_log(avctx, AV_LOG_ERROR, "Could not allocate frame.\n"); 202 return AVERROR(ENOMEM); 203 } 204 205 ctx->size = avpicture_get_size(avctx->pix_fmt, 206 avctx->width, avctx->height); 207 208 ctx->val = av_malloc(ctx->size * sizeof(*ctx->val)); 209 210 if (!ctx->val) { 211 av_log(avctx, AV_LOG_ERROR, "Could not allocate values buffer.\n"); 212 vble_decode_close(avctx); 213 return AVERROR(ENOMEM); 214 } 215 216 return 0; 217} 218 219AVCodec ff_vble_decoder = { 220 .name = "vble", 221 .type = AVMEDIA_TYPE_VIDEO, 222 .id = CODEC_ID_VBLE, 223 .priv_data_size = sizeof(VBLEContext), 224 .init = vble_decode_init, 225 .close = vble_decode_close, 226 .decode = vble_decode_frame, 227 .capabilities = CODEC_CAP_DR1, 228 .long_name = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"), 229}; 230