libavcodec/vble.c

   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 #include "internal.h"
  33 #include "mathops.h"
  34
  35 typedef struct {
  36     AVCodecContext *avctx;
  37     DSPContext dsp;
  38
  39     int            size;
  40     uint8_t        *val; /* First holds the lengths of vlc symbols and then their values */
  41 } VBLEContext;
  42
  43 static uint8_t vble_read_reverse_unary(GetBitContext *gb)
  44 {
  45     /* At most we need to read 9 bits total to get indices up to 8 */
  46     uint8_t val = show_bits(gb, 8);
  47
  48     if (val) {
  49         val = 7 - av_log2_16bit(ff_reverse[val]);
  50         skip_bits(gb, val + 1);
  51         return val;
  52     } else {
  53         skip_bits(gb, 8);
  54         if (get_bits1(gb))
  55             return 8;
  56     }
  57
  58     /* Return something larger than 8 on error */
  59     return UINT8_MAX;
  60 }
  61
  62 static int vble_unpack(VBLEContext *ctx, GetBitContext *gb)
  63 {
  64     int i;
  65
  66     /* Read all the lengths in first */
  67     for (i = 0; i < ctx->size; i++) {
  68         ctx->val[i] = vble_read_reverse_unary(gb);
  69
  70         if (ctx->val[i] == UINT8_MAX)
  71             return -1;
  72     }
  73
  74     for (i = 0; i < ctx->size; i++) {
  75         /* Check we have enough bits left */
  76         if (get_bits_left(gb) < ctx->val[i])
  77             return -1;
  78
  79         /* get_bits can't take a length of 0 */
  80         if (ctx->val[i])
  81             ctx->val[i] = (1 << ctx->val[i]) + get_bits(gb, ctx->val[i]) - 1;
  82     }
  83
  84     return 0;
  85 }
  86
  87 static void vble_restore_plane(VBLEContext *ctx, AVFrame *pic,
  88                                int plane, int offset,
  89                                int width, int height)
  90 {
  91     uint8_t *dst = pic->data[plane];
  92     uint8_t *val = ctx->val + offset;
  93     int stride = pic->linesize[plane];
  94     int i, j, left, left_top;
  95
  96     for (i = 0; i < height; i++) {
  97         for (j = 0; j < width; j++)
  98             val[j] = (val[j] >> 1) ^ -(val[j] & 1);
  99
 100         if (i) {
 101             left = 0;
 102             left_top = dst[-stride];
 103             ctx->dsp.add_hfyu_median_prediction(dst, dst-stride, val,
 104                                                 width, &left, &left_top);
 105         } else {
 106             dst[0] = val[0];
 107             for (j = 1; j < width; j++)
 108                 dst[j] = val[j] + dst[j - 1];
 109         }
 110         dst += stride;
 111         val += width;
 112     }
 113 }
 114
 115 static int vble_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
 116                              AVPacket *avpkt)
 117 {
 118     VBLEContext *ctx = avctx->priv_data;
 119     AVFrame *pic     = data;
 120     GetBitContext gb;
 121     const uint8_t *src = avpkt->data;
 122     int version;
 123     int offset = 0;
 124     int width_uv = avctx->width / 2, height_uv = avctx->height / 2;
 125
 126     /* Allocate buffer */
 127     if (ff_get_buffer(avctx, pic, 0) < 0) {
 128         av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");
 129         return AVERROR(ENOMEM);
 130     }
 131
 132     /* Set flags */
 133     pic->key_frame = 1;
 134     pic->pict_type = AV_PICTURE_TYPE_I;
 135
 136     /* Version should always be 1 */
 137     version = AV_RL32(src);
 138
 139     if (version != 1)
 140         av_log(avctx, AV_LOG_WARNING, "Unsupported VBLE Version: %d\n", version);
 141
 142     init_get_bits(&gb, src + 4, (avpkt->size - 4) * 8);
 143
 144     /* Unpack */
 145     if (vble_unpack(ctx, &gb) < 0) {
 146         av_log(avctx, AV_LOG_ERROR, "Invalid Code\n");
 147         return AVERROR_INVALIDDATA;
 148     }
 149
 150     /* Restore planes. Should be almost identical to Huffyuv's. */
 151     vble_restore_plane(ctx, pic, 0, offset, avctx->width, avctx->height);
 152
 153     /* Chroma */
 154     if (!(ctx->avctx->flags & CODEC_FLAG_GRAY)) {
 155         offset += avctx->width * avctx->height;
 156         vble_restore_plane(ctx, pic, 1, offset, width_uv, height_uv);
 157
 158         offset += width_uv * height_uv;
 159         vble_restore_plane(ctx, pic, 2, offset, width_uv, height_uv);
 160     }
 161
 162     *got_frame       = 1;
 163
 164     return avpkt->size;
 165 }
 166
 167 static av_cold int vble_decode_close(AVCodecContext *avctx)
 168 {
 169     VBLEContext *ctx = avctx->priv_data;
 170     av_freep(&ctx->val);
 171
 172     return 0;
 173 }
 174
 175 static av_cold int vble_decode_init(AVCodecContext *avctx)
 176 {
 177     VBLEContext *ctx = avctx->priv_data;
 178
 179     /* Stash for later use */
 180     ctx->avctx = avctx;
 181     ff_dsputil_init(&ctx->dsp, avctx);
 182
 183     avctx->pix_fmt = AV_PIX_FMT_YUV420P;
 184     avctx->bits_per_raw_sample = 8;
 185
 186     ctx->size = avpicture_get_size(avctx->pix_fmt,
 187                                    avctx->width, avctx->height);
 188
 189     ctx->val = av_malloc(ctx->size * sizeof(*ctx->val));
 190
 191     if (!ctx->val) {
 192         av_log(avctx, AV_LOG_ERROR, "Could not allocate values buffer.\n");
 193         vble_decode_close(avctx);
 194         return AVERROR(ENOMEM);
 195     }
 196
 197     return 0;
 198 }
 199
 200 AVCodec ff_vble_decoder = {
 201     .name           = "vble",
 202     .type           = AVMEDIA_TYPE_VIDEO,
 203     .id             = AV_CODEC_ID_VBLE,
 204     .priv_data_size = sizeof(VBLEContext),
 205     .init           = vble_decode_init,
 206     .close          = vble_decode_close,
 207     .decode         = vble_decode_frame,
 208     .capabilities   = CODEC_CAP_DR1,
 209     .long_name      = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
 210 };