FFmpeg: libavcodec/qpeg.c Source File

00001 /*
00002  * QPEG codec
00003  * Copyright (c) 2004 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 
00029 typedef struct QpegContext{
00030     AVCodecContext *avctx;
00031     AVFrame pic, ref;
00032     uint32_t pal[256];
00033 } QpegContext;
00034 
00035 static int qpeg_decode_intra(const uint8_t *src, uint8_t *dst, int size,
00036                             int stride, int width, int height)
00037 {
00038     int i;
00039     int code;
00040     int c0, c1;
00041     int run, copy;
00042     int filled = 0;
00043     int rows_to_go;
00044 
00045     rows_to_go = height;
00046     height--;
00047     dst = dst + height * stride;
00048 
00049     while((size > 0) && (rows_to_go > 0)) {
00050         code = *src++;
00051         size--;
00052         run = copy = 0;
00053         if(code == 0xFC) /* end-of-picture code */
00054             break;
00055         if(code >= 0xF8) { /* very long run */
00056             c0 = *src++;
00057             c1 = *src++;
00058             size -= 2;
00059             run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;
00060         } else if (code >= 0xF0) { /* long run */
00061             c0 = *src++;
00062             size--;
00063             run = ((code & 0xF) << 8) + c0 + 2;
00064         } else if (code >= 0xE0) { /* short run */
00065             run = (code & 0x1F) + 2;
00066         } else if (code >= 0xC0) { /* very long copy */
00067             c0 = *src++;
00068             c1 = *src++;
00069             size -= 2;
00070             copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;
00071         } else if (code >= 0x80) { /* long copy */
00072             c0 = *src++;
00073             size--;
00074             copy = ((code & 0x7F) << 8) + c0 + 1;
00075         } else { /* short copy */
00076             copy = code + 1;
00077         }
00078 
00079         /* perform actual run or copy */
00080         if(run) {
00081             int p;
00082 
00083             p = *src++;
00084             size--;
00085             for(i = 0; i < run; i++) {
00086                 dst[filled++] = p;
00087                 if (filled >= width) {
00088                     filled = 0;
00089                     dst -= stride;
00090                     rows_to_go--;
00091                     if(rows_to_go <= 0)
00092                         break;
00093                 }
00094             }
00095         } else {
00096             size -= copy;
00097             if (size<0)
00098                 return AVERROR_INVALIDDATA;
00099             for(i = 0; i < copy; i++) {
00100                 dst[filled++] = *src++;
00101                 if (filled >= width) {
00102                     filled = 0;
00103                     dst -= stride;
00104                     rows_to_go--;
00105                     if(rows_to_go <= 0)
00106                         break;
00107                 }
00108             }
00109         }
00110     }
00111     return 0;
00112 }
00113 
00114 static const int qpeg_table_h[16] =
00115  { 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};
00116 static const int qpeg_table_w[16] =
00117  { 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};
00118 
00119 /* Decodes delta frames */
00120 static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
00121                             int stride, int width, int height,
00122                             int delta, const uint8_t *ctable, uint8_t *refdata)
00123 {
00124     int i, j;
00125     int code;
00126     int filled = 0;
00127     int orig_height;
00128 
00129     if(!refdata)
00130         refdata= dst;
00131 
00132     /* copy prev frame */
00133     for(i = 0; i < height; i++)
00134         memcpy(dst + (i * stride), refdata + (i * stride), width);
00135 
00136     orig_height = height;
00137     height--;
00138     dst = dst + height * stride;
00139 
00140     while((size > 0) && (height >= 0)) {
00141         code = *src++;
00142         size--;
00143 
00144         if(delta) {
00145             /* motion compensation */
00146             while((code & 0xF0) == 0xF0) {
00147                 if(delta == 1) {
00148                     int me_idx;
00149                     int me_w, me_h, me_x, me_y;
00150                     uint8_t *me_plane;
00151                     int corr, val;
00152 
00153                     /* get block size by index */
00154                     me_idx = code & 0xF;
00155                     me_w = qpeg_table_w[me_idx];
00156                     me_h = qpeg_table_h[me_idx];
00157 
00158                     /* extract motion vector */
00159                     corr = *src++;
00160                     size--;
00161 
00162                     val = corr >> 4;
00163                     if(val > 7)
00164                         val -= 16;
00165                     me_x = val;
00166 
00167                     val = corr & 0xF;
00168                     if(val > 7)
00169                         val -= 16;
00170                     me_y = val;
00171 
00172                     /* check motion vector */
00173                     if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||
00174                        (height - me_y - me_h < 0) || (height - me_y > orig_height) ||
00175                        (filled + me_w > width) || (height - me_h < 0))
00176                         av_log(NULL, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",
00177                                me_x, me_y, me_w, me_h, filled, height);
00178                     else {
00179                         /* do motion compensation */
00180                         me_plane = refdata + (filled + me_x) + (height - me_y) * stride;
00181                         for(j = 0; j < me_h; j++) {
00182                             for(i = 0; i < me_w; i++)
00183                                 dst[filled + i - (j * stride)] = me_plane[i - (j * stride)];
00184                         }
00185                     }
00186                 }
00187                 code = *src++;
00188                 size--;
00189             }
00190         }
00191 
00192         if(code == 0xE0) /* end-of-picture code */
00193             break;
00194         if(code > 0xE0) { /* run code: 0xE1..0xFF */
00195             int p;
00196 
00197             code &= 0x1F;
00198             p = *src++;
00199             size--;
00200             for(i = 0; i <= code; i++) {
00201                 dst[filled++] = p;
00202                 if(filled >= width) {
00203                     filled = 0;
00204                     dst -= stride;
00205                     height--;
00206                     if(height < 0)
00207                         break;
00208                 }
00209             }
00210         } else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */
00211             code &= 0x1F;
00212 
00213             for(i = 0; i <= code; i++) {
00214                 dst[filled++] = *src++;
00215                 if(filled >= width) {
00216                     filled = 0;
00217                     dst -= stride;
00218                     height--;
00219                     if(height < 0)
00220                         break;
00221                 }
00222             }
00223             size -= code + 1;
00224         } else if(code >= 0x80) { /* skip code: 0x80..0xBF */
00225             int skip;
00226 
00227             code &= 0x3F;
00228             /* codes 0x80 and 0x81 are actually escape codes,
00229                skip value minus constant is in the next byte */
00230             if(!code)
00231                 skip = (*src++) + 64;
00232             else if(code == 1)
00233                 skip = (*src++) + 320;
00234             else
00235                 skip = code;
00236             filled += skip;
00237             while( filled >= width) {
00238                 filled -= width;
00239                 dst -= stride;
00240                 height--;
00241                 if(height < 0)
00242                     break;
00243             }
00244         } else {
00245             /* zero code treated as one-pixel skip */
00246             if(code)
00247                 dst[filled++] = ctable[code & 0x7F];
00248             else
00249                 filled++;
00250             if(filled >= width) {
00251                 filled = 0;
00252                 dst -= stride;
00253                 height--;
00254             }
00255         }
00256     }
00257 }
00258 
00259 static int decode_frame(AVCodecContext *avctx,
00260                         void *data, int *data_size,
00261                         AVPacket *avpkt)
00262 {
00263     const uint8_t *buf = avpkt->data;
00264     int buf_size = avpkt->size;
00265     QpegContext * const a = avctx->priv_data;
00266     AVFrame * p= (AVFrame*)&a->pic;
00267     AVFrame * ref= (AVFrame*)&a->ref;
00268     uint8_t* outdata;
00269     int delta, ret = 0;
00270     const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
00271 
00272     if(ref->data[0])
00273         avctx->release_buffer(avctx, ref);
00274     FFSWAP(AVFrame, *ref, *p);
00275 
00276     p->reference= 3;
00277     if(avctx->get_buffer(avctx, p) < 0){
00278         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00279         return -1;
00280     }
00281     outdata = a->pic.data[0];
00282     if(buf[0x85] == 0x10) {
00283         ret = qpeg_decode_intra(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height);
00284     } else {
00285         delta = buf[0x85];
00286         qpeg_decode_inter(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height, delta, buf + 4, a->ref.data[0]);
00287     }
00288 
00289     if (ret<0)
00290         return ret;
00291 
00292     /* make the palette available on the way out */
00293     if (pal) {
00294         a->pic.palette_has_changed = 1;
00295         memcpy(a->pal, pal, AVPALETTE_SIZE);
00296     }
00297     memcpy(a->pic.data[1], a->pal, AVPALETTE_SIZE);
00298 
00299     *data_size = sizeof(AVFrame);
00300     *(AVFrame*)data = a->pic;
00301 
00302     return buf_size;
00303 }
00304 
00305 static av_cold int decode_init(AVCodecContext *avctx){
00306     QpegContext * const a = avctx->priv_data;
00307 
00308     avcodec_get_frame_defaults(&a->pic);
00309     avcodec_get_frame_defaults(&a->ref);
00310     a->avctx = avctx;
00311     avctx->pix_fmt= PIX_FMT_PAL8;
00312 
00313     return 0;
00314 }
00315 
00316 static av_cold int decode_end(AVCodecContext *avctx){
00317     QpegContext * const a = avctx->priv_data;
00318     AVFrame * const p= (AVFrame*)&a->pic;
00319     AVFrame * const ref= (AVFrame*)&a->ref;
00320 
00321     if(p->data[0])
00322         avctx->release_buffer(avctx, p);
00323     if(ref->data[0])
00324         avctx->release_buffer(avctx, ref);
00325 
00326     return 0;
00327 }
00328 
00329 AVCodec ff_qpeg_decoder = {
00330     .name           = "qpeg",
00331     .type           = AVMEDIA_TYPE_VIDEO,
00332     .id             = CODEC_ID_QPEG,
00333     .priv_data_size = sizeof(QpegContext),
00334     .init           = decode_init,
00335     .close          = decode_end,
00336     .decode         = decode_frame,
00337     .capabilities   = CODEC_CAP_DR1,
00338     .long_name = NULL_IF_CONFIG_SMALL("Q-team QPEG"),
00339 };