libavcodec/vble.c
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00001 /*
00002  * VBLE Decoder
00003  * Copyright (c) 2011 Derek Buitenhuis
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00027 #define BITSTREAM_READER_LE
00028 
00029 #include "avcodec.h"
00030 #include "dsputil.h"
00031 #include "get_bits.h"
00032 
00033 typedef struct {
00034     AVCodecContext *avctx;
00035     DSPContext dsp;
00036 
00037     int            size;
00038     uint8_t        *val; 
00039 } VBLEContext;
00040 
00041 static int vble_unpack(VBLEContext *ctx, GetBitContext *gb)
00042 {
00043     int i;
00044     int allbits = 0;
00045     static const uint8_t LUT[256] = {
00046         8,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
00047         5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
00048         6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
00049         5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
00050         7,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
00051         5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
00052         6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
00053         5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
00054     };
00055 
00056     /* Read all the lengths in first */
00057     for (i = 0; i < ctx->size; i++) {
00058         /* At most we need to read 9 bits total to get indices up to 8 */
00059         int val = show_bits(gb, 8);
00060 
00061         // read reverse unary
00062         if (val) {
00063             val = LUT[val];
00064             skip_bits(gb, val + 1);
00065             ctx->val[i] = val;
00066         } else {
00067             skip_bits(gb, 8);
00068             if (!get_bits1(gb))
00069                 return -1;
00070             ctx->val[i] = 8;
00071         }
00072         allbits += ctx->val[i];
00073     }
00074 
00075     /* Check we have enough bits left */
00076     if (get_bits_left(gb) < allbits)
00077         return -1;
00078     return 0;
00079 }
00080 
00081 static void vble_restore_plane(VBLEContext *ctx, GetBitContext *gb, int plane,
00082                                int offset, int width, int height)
00083 {
00084     AVFrame *pic = ctx->avctx->coded_frame;
00085     uint8_t *dst = pic->data[plane];
00086     uint8_t *val = ctx->val + offset;
00087     int stride = pic->linesize[plane];
00088     int i, j, left, left_top;
00089 
00090     for (i = 0; i < height; i++) {
00091         for (j = 0; j < width; j++) {
00092             /* get_bits can't take a length of 0 */
00093             if (val[j]) {
00094                 int v = (1 << val[j]) + get_bits(gb, val[j]) - 1;
00095                 val[j] = (v >> 1) ^ -(v & 1);
00096             }
00097         }
00098         if (i) {
00099             left = 0;
00100             left_top = dst[-stride];
00101             ctx->dsp.add_hfyu_median_prediction(dst, dst-stride, val, width, &left, &left_top);
00102         } else {
00103             dst[0] = val[0];
00104             for (j = 1; j < width; j++)
00105                 dst[j] = val[j] + dst[j - 1];
00106         }
00107         dst += stride;
00108         val += width;
00109     }
00110 }
00111 
00112 static int vble_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
00113                              AVPacket *avpkt)
00114 {
00115     VBLEContext *ctx = avctx->priv_data;
00116     AVFrame *pic = avctx->coded_frame;
00117     GetBitContext gb;
00118     const uint8_t *src = avpkt->data;
00119     int version;
00120     int offset = 0;
00121     int width_uv = avctx->width / 2, height_uv = avctx->height / 2;
00122 
00123     pic->reference = 0;
00124 
00125     /* Clear buffer if need be */
00126     if (pic->data[0])
00127         avctx->release_buffer(avctx, pic);
00128 
00129     /* Allocate buffer */
00130     if (avctx->get_buffer(avctx, pic) < 0) {
00131         av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");
00132         return AVERROR(ENOMEM);
00133     }
00134 
00135     /* Set flags */
00136     pic->key_frame = 1;
00137     pic->pict_type = AV_PICTURE_TYPE_I;
00138 
00139     /* Version should always be 1 */
00140     version = AV_RL32(src);
00141 
00142     if (version != 1) {
00143         av_log(avctx, AV_LOG_ERROR, "Unsupported VBLE Version: %d\n", version);
00144         return AVERROR_INVALIDDATA;
00145     }
00146 
00147     init_get_bits(&gb, src + 4, (avpkt->size - 4) * 8);
00148 
00149     /* Unpack */
00150     if (vble_unpack(ctx, &gb) < 0) {
00151         av_log(avctx, AV_LOG_ERROR, "Invalid Code\n");
00152         return AVERROR_INVALIDDATA;
00153     }
00154 
00155     /* Restore planes. Should be almost identical to Huffyuv's. */
00156     vble_restore_plane(ctx, &gb, 0, offset, avctx->width, avctx->height);
00157 
00158     /* Chroma */
00159     if (!(ctx->avctx->flags & CODEC_FLAG_GRAY)) {
00160         offset += avctx->width * avctx->height;
00161         vble_restore_plane(ctx, &gb, 1, offset, width_uv, height_uv);
00162 
00163         offset += width_uv * height_uv;
00164         vble_restore_plane(ctx, &gb, 2, offset, width_uv, height_uv);
00165     }
00166 
00167     *data_size = sizeof(AVFrame);
00168     *(AVFrame *)data = *pic;
00169 
00170     return avpkt->size;
00171 }
00172 
00173 static av_cold int vble_decode_close(AVCodecContext *avctx)
00174 {
00175     VBLEContext *ctx = avctx->priv_data;
00176     AVFrame *pic = avctx->coded_frame;
00177 
00178     if (pic->data[0])
00179         avctx->release_buffer(avctx, pic);
00180 
00181     av_freep(&avctx->coded_frame);
00182     av_freep(&ctx->val);
00183 
00184     return 0;
00185 }
00186 
00187 static av_cold int vble_decode_init(AVCodecContext *avctx)
00188 {
00189     VBLEContext *ctx = avctx->priv_data;
00190 
00191     /* Stash for later use */
00192     ctx->avctx = avctx;
00193     dsputil_init(&ctx->dsp, avctx);
00194 
00195     avctx->pix_fmt = PIX_FMT_YUV420P;
00196     avctx->bits_per_raw_sample = 8;
00197     avctx->coded_frame = avcodec_alloc_frame();
00198 
00199     if (!avctx->coded_frame) {
00200         av_log(avctx, AV_LOG_ERROR, "Could not allocate frame.\n");
00201         return AVERROR(ENOMEM);
00202     }
00203 
00204     ctx->size = avpicture_get_size(avctx->pix_fmt,
00205                                    avctx->width, avctx->height);
00206 
00207     ctx->val = av_malloc(ctx->size * sizeof(*ctx->val));
00208 
00209     if (!ctx->val) {
00210         av_log(avctx, AV_LOG_ERROR, "Could not allocate values buffer.\n");
00211         vble_decode_close(avctx);
00212         return AVERROR(ENOMEM);
00213     }
00214 
00215     return 0;
00216 }
00217 
00218 AVCodec ff_vble_decoder = {
00219     .name           = "vble",
00220     .type           = AVMEDIA_TYPE_VIDEO,
00221     .id             = CODEC_ID_VBLE,
00222     .priv_data_size = sizeof(VBLEContext),
00223     .init           = vble_decode_init,
00224     .close          = vble_decode_close,
00225     .decode         = vble_decode_frame,
00226     .capabilities   = CODEC_CAP_DR1,
00227     .long_name      = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
00228 };