FFmpeg: libavcodec/loco.c Source File

00001 /*
00002  * LOCO codec
00003  * Copyright (c) 2005 Konstantin Shishkov
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 #include "avcodec.h"
00028 #include "get_bits.h"
00029 #include "golomb.h"
00030 #include "mathops.h"
00031 
00032 enum LOCO_MODE {LOCO_UNKN=0, LOCO_CYUY2=-1, LOCO_CRGB=-2, LOCO_CRGBA=-3, LOCO_CYV12=-4,
00033  LOCO_YUY2=1, LOCO_UYVY=2, LOCO_RGB=3, LOCO_RGBA=4, LOCO_YV12=5};
00034 
00035 typedef struct LOCOContext{
00036     AVCodecContext *avctx;
00037     AVFrame pic;
00038     int lossy;
00039     int mode;
00040 } LOCOContext;
00041 
00042 typedef struct RICEContext{
00043     GetBitContext gb;
00044     int save, run, run2; /* internal rice decoder state */
00045     int sum, count; /* sum and count for getting rice parameter */
00046     int lossy;
00047 }RICEContext;
00048 
00049 static int loco_get_rice_param(RICEContext *r)
00050 {
00051     int cnt = 0;
00052     int val = r->count;
00053 
00054     while(r->sum > val && cnt < 9) {
00055         val <<= 1;
00056         cnt++;
00057     }
00058 
00059     return cnt;
00060 }
00061 
00062 static inline void loco_update_rice_param(RICEContext *r, int val)
00063 {
00064     r->sum += val;
00065     r->count++;
00066 
00067     if(r->count == 16) {
00068         r->sum >>= 1;
00069         r->count >>= 1;
00070     }
00071 }
00072 
00073 static inline int loco_get_rice(RICEContext *r)
00074 {
00075     int v;
00076     if (r->run > 0) { /* we have zero run */
00077         r->run--;
00078         loco_update_rice_param(r, 0);
00079         return 0;
00080     }
00081     v = get_ur_golomb_jpegls(&r->gb, loco_get_rice_param(r), INT_MAX, 0);
00082     loco_update_rice_param(r, (v+1)>>1);
00083     if (!v) {
00084         if (r->save >= 0) {
00085             r->run = get_ur_golomb_jpegls(&r->gb, 2, INT_MAX, 0);
00086             if(r->run > 1)
00087                 r->save += r->run + 1;
00088             else
00089                 r->save -= 3;
00090         }
00091         else
00092             r->run2++;
00093     } else {
00094         v = ((v>>1) + r->lossy) ^ -(v&1);
00095         if (r->run2 > 0) {
00096             if (r->run2 > 2)
00097                 r->save += r->run2;
00098             else
00099                 r->save -= 3;
00100             r->run2 = 0;
00101         }
00102     }
00103 
00104     return v;
00105 }
00106 
00107 /* LOCO main predictor - LOCO-I/JPEG-LS predictor */
00108 static inline int loco_predict(uint8_t* data, int stride, int step)
00109 {
00110     int a, b, c;
00111 
00112     a = data[-stride];
00113     b = data[-step];
00114     c = data[-stride - step];
00115 
00116     return mid_pred(a, a + b - c, b);
00117 }
00118 
00119 static int loco_decode_plane(LOCOContext *l, uint8_t *data, int width, int height,
00120                              int stride, const uint8_t *buf, int buf_size, int step)
00121 {
00122     RICEContext rc;
00123     int val;
00124     int i, j;
00125 
00126     init_get_bits(&rc.gb, buf, buf_size*8);
00127     rc.save = 0;
00128     rc.run = 0;
00129     rc.run2 = 0;
00130     rc.lossy = l->lossy;
00131 
00132     rc.sum = 8;
00133     rc.count = 1;
00134 
00135     /* restore top left pixel */
00136     val = loco_get_rice(&rc);
00137     data[0] = 128 + val;
00138     /* restore top line */
00139     for (i = 1; i < width; i++) {
00140         val = loco_get_rice(&rc);
00141         data[i * step] = data[i * step - step] + val;
00142     }
00143     data += stride;
00144     for (j = 1; j < height; j++) {
00145         /* restore left column */
00146         val = loco_get_rice(&rc);
00147         data[0] = data[-stride] + val;
00148         /* restore all other pixels */
00149         for (i = 1; i < width; i++) {
00150             val = loco_get_rice(&rc);
00151             data[i * step] = loco_predict(&data[i * step], stride, step) + val;
00152         }
00153         data += stride;
00154     }
00155 
00156     return (get_bits_count(&rc.gb) + 7) >> 3;
00157 }
00158 
00159 static int decode_frame(AVCodecContext *avctx,
00160                         void *data, int *data_size,
00161                         AVPacket *avpkt)
00162 {
00163     const uint8_t *buf = avpkt->data;
00164     int buf_size = avpkt->size;
00165     LOCOContext * const l = avctx->priv_data;
00166     AVFrame * const p= (AVFrame*)&l->pic;
00167     int decoded;
00168 
00169     if(p->data[0])
00170         avctx->release_buffer(avctx, p);
00171 
00172     p->reference = 0;
00173     if(avctx->get_buffer(avctx, p) < 0){
00174         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00175         return -1;
00176     }
00177     p->key_frame = 1;
00178 
00179     switch(l->mode) {
00180     case LOCO_CYUY2: case LOCO_YUY2: case LOCO_UYVY:
00181         decoded = loco_decode_plane(l, p->data[0], avctx->width, avctx->height,
00182                                     p->linesize[0], buf, buf_size, 1);
00183         buf += decoded; buf_size -= decoded;
00184         decoded = loco_decode_plane(l, p->data[1], avctx->width / 2, avctx->height,
00185                                     p->linesize[1], buf, buf_size, 1);
00186         buf += decoded; buf_size -= decoded;
00187         decoded = loco_decode_plane(l, p->data[2], avctx->width / 2, avctx->height,
00188                                     p->linesize[2], buf, buf_size, 1);
00189         break;
00190     case LOCO_CYV12: case LOCO_YV12:
00191         decoded = loco_decode_plane(l, p->data[0], avctx->width, avctx->height,
00192                                     p->linesize[0], buf, buf_size, 1);
00193         buf += decoded; buf_size -= decoded;
00194         decoded = loco_decode_plane(l, p->data[2], avctx->width / 2, avctx->height / 2,
00195                                     p->linesize[2], buf, buf_size, 1);
00196         buf += decoded; buf_size -= decoded;
00197         decoded = loco_decode_plane(l, p->data[1], avctx->width / 2, avctx->height / 2,
00198                                     p->linesize[1], buf, buf_size, 1);
00199         break;
00200     case LOCO_CRGB: case LOCO_RGB:
00201         decoded = loco_decode_plane(l, p->data[0] + p->linesize[0]*(avctx->height-1), avctx->width, avctx->height,
00202                                     -p->linesize[0], buf, buf_size, 3);
00203         buf += decoded; buf_size -= decoded;
00204         decoded = loco_decode_plane(l, p->data[0] + p->linesize[0]*(avctx->height-1) + 1, avctx->width, avctx->height,
00205                                     -p->linesize[0], buf, buf_size, 3);
00206         buf += decoded; buf_size -= decoded;
00207         decoded = loco_decode_plane(l, p->data[0] + p->linesize[0]*(avctx->height-1) + 2, avctx->width, avctx->height,
00208                                     -p->linesize[0], buf, buf_size, 3);
00209         break;
00210     case LOCO_RGBA:
00211         decoded = loco_decode_plane(l, p->data[0], avctx->width, avctx->height,
00212                                     p->linesize[0], buf, buf_size, 4);
00213         buf += decoded; buf_size -= decoded;
00214         decoded = loco_decode_plane(l, p->data[0] + 1, avctx->width, avctx->height,
00215                                     p->linesize[0], buf, buf_size, 4);
00216         buf += decoded; buf_size -= decoded;
00217         decoded = loco_decode_plane(l, p->data[0] + 2, avctx->width, avctx->height,
00218                                     p->linesize[0], buf, buf_size, 4);
00219         buf += decoded; buf_size -= decoded;
00220         decoded = loco_decode_plane(l, p->data[0] + 3, avctx->width, avctx->height,
00221                                     p->linesize[0], buf, buf_size, 4);
00222         break;
00223     }
00224 
00225     *data_size = sizeof(AVFrame);
00226     *(AVFrame*)data = l->pic;
00227 
00228     return buf_size;
00229 }
00230 
00231 static av_cold int decode_init(AVCodecContext *avctx){
00232     LOCOContext * const l = avctx->priv_data;
00233     int version;
00234 
00235     l->avctx = avctx;
00236     if (avctx->extradata_size < 12) {
00237         av_log(avctx, AV_LOG_ERROR, "Extradata size must be >= 12 instead of %i\n",
00238                avctx->extradata_size);
00239         return -1;
00240     }
00241     version = AV_RL32(avctx->extradata);
00242     switch(version) {
00243     case 1:
00244         l->lossy = 0;
00245         break;
00246     case 2:
00247         l->lossy = AV_RL32(avctx->extradata + 8);
00248         break;
00249     default:
00250         l->lossy = AV_RL32(avctx->extradata + 8);
00251         av_log_ask_for_sample(avctx, "This is LOCO codec version %i.\n", version);
00252     }
00253 
00254     l->mode = AV_RL32(avctx->extradata + 4);
00255     switch(l->mode) {
00256     case LOCO_CYUY2: case LOCO_YUY2: case LOCO_UYVY:
00257         avctx->pix_fmt = PIX_FMT_YUV422P;
00258         break;
00259     case LOCO_CRGB: case LOCO_RGB:
00260         avctx->pix_fmt = PIX_FMT_BGR24;
00261         break;
00262     case LOCO_CYV12: case LOCO_YV12:
00263         avctx->pix_fmt = PIX_FMT_YUV420P;
00264         break;
00265     case LOCO_CRGBA: case LOCO_RGBA:
00266         avctx->pix_fmt = PIX_FMT_RGB32;
00267         break;
00268     default:
00269         av_log(avctx, AV_LOG_INFO, "Unknown colorspace, index = %i\n", l->mode);
00270         return -1;
00271     }
00272     if(avctx->debug & FF_DEBUG_PICT_INFO)
00273         av_log(avctx, AV_LOG_INFO, "lossy:%i, version:%i, mode: %i\n", l->lossy, version, l->mode);
00274 
00275     avcodec_get_frame_defaults(&l->pic);
00276 
00277     return 0;
00278 }
00279 
00280 static av_cold int decode_end(AVCodecContext *avctx){
00281     LOCOContext * const l = avctx->priv_data;
00282     AVFrame *pic = &l->pic;
00283 
00284     if (pic->data[0])
00285         avctx->release_buffer(avctx, pic);
00286 
00287     return 0;
00288 }
00289 
00290 AVCodec ff_loco_decoder = {
00291     "loco",
00292     AVMEDIA_TYPE_VIDEO,
00293     CODEC_ID_LOCO,
00294     sizeof(LOCOContext),
00295     decode_init,
00296     NULL,
00297     decode_end,
00298     decode_frame,
00299     CODEC_CAP_DR1,
00300     .long_name = NULL_IF_CONFIG_SMALL("LOCO"),
00301 };