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 void 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             for(i = 0; i < copy; i++) {
00098                 dst[filled++] = *src++;
00099                 if (filled >= width) {
00100                     filled = 0;
00101                     dst -= stride;
00102                     rows_to_go--;
00103                     if(rows_to_go <= 0)
00104                         break;
00105                 }
00106             }
00107         }
00108     }
00109 }
00110 
00111 static const int qpeg_table_h[16] =
00112  { 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};
00113 static const int qpeg_table_w[16] =
00114  { 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};
00115 
00116 /* Decodes delta frames */
00117 static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
00118                             int stride, int width, int height,
00119                             int delta, const uint8_t *ctable, uint8_t *refdata)
00120 {
00121     int i, j;
00122     int code;
00123     int filled = 0;
00124     int orig_height;
00125 
00126     if(!refdata)
00127         refdata= dst;
00128 
00129     /* copy prev frame */
00130     for(i = 0; i < height; i++)
00131         memcpy(dst + (i * stride), refdata + (i * stride), width);
00132 
00133     orig_height = height;
00134     height--;
00135     dst = dst + height * stride;
00136 
00137     while((size > 0) && (height >= 0)) {
00138         code = *src++;
00139         size--;
00140 
00141         if(delta) {
00142             /* motion compensation */
00143             while((code & 0xF0) == 0xF0) {
00144                 if(delta == 1) {
00145                     int me_idx;
00146                     int me_w, me_h, me_x, me_y;
00147                     uint8_t *me_plane;
00148                     int corr, val;
00149 
00150                     /* get block size by index */
00151                     me_idx = code & 0xF;
00152                     me_w = qpeg_table_w[me_idx];
00153                     me_h = qpeg_table_h[me_idx];
00154 
00155                     /* extract motion vector */
00156                     corr = *src++;
00157                     size--;
00158 
00159                     val = corr >> 4;
00160                     if(val > 7)
00161                         val -= 16;
00162                     me_x = val;
00163 
00164                     val = corr & 0xF;
00165                     if(val > 7)
00166                         val -= 16;
00167                     me_y = val;
00168 
00169                     /* check motion vector */
00170                     if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||
00171                        (height - me_y - me_h < 0) || (height - me_y > orig_height) ||
00172                        (filled + me_w > width) || (height - me_h < 0))
00173                         av_log(NULL, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",
00174                                me_x, me_y, me_w, me_h, filled, height);
00175                     else {
00176                         /* do motion compensation */
00177                         me_plane = refdata + (filled + me_x) + (height - me_y) * stride;
00178                         for(j = 0; j < me_h; j++) {
00179                             for(i = 0; i < me_w; i++)
00180                                 dst[filled + i - (j * stride)] = me_plane[i - (j * stride)];
00181                         }
00182                     }
00183                 }
00184                 code = *src++;
00185                 size--;
00186             }
00187         }
00188 
00189         if(code == 0xE0) /* end-of-picture code */
00190             break;
00191         if(code > 0xE0) { /* run code: 0xE1..0xFF */
00192             int p;
00193 
00194             code &= 0x1F;
00195             p = *src++;
00196             size--;
00197             for(i = 0; i <= code; i++) {
00198                 dst[filled++] = p;
00199                 if(filled >= width) {
00200                     filled = 0;
00201                     dst -= stride;
00202                     height--;
00203                 }
00204             }
00205         } else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */
00206             code &= 0x1F;
00207 
00208             for(i = 0; i <= code; i++) {
00209                 dst[filled++] = *src++;
00210                 if(filled >= width) {
00211                     filled = 0;
00212                     dst -= stride;
00213                     height--;
00214                 }
00215             }
00216             size -= code + 1;
00217         } else if(code >= 0x80) { /* skip code: 0x80..0xBF */
00218             int skip;
00219 
00220             code &= 0x3F;
00221             /* codes 0x80 and 0x81 are actually escape codes,
00222                skip value minus constant is in the next byte */
00223             if(!code)
00224                 skip = (*src++) + 64;
00225             else if(code == 1)
00226                 skip = (*src++) + 320;
00227             else
00228                 skip = code;
00229             filled += skip;
00230             while( filled >= width) {
00231                 filled -= width;
00232                 dst -= stride;
00233                 height--;
00234                 if(height < 0)
00235                     break;
00236             }
00237         } else {
00238             /* zero code treated as one-pixel skip */
00239             if(code)
00240                 dst[filled++] = ctable[code & 0x7F];
00241             else
00242                 filled++;
00243             if(filled >= width) {
00244                 filled = 0;
00245                 dst -= stride;
00246                 height--;
00247             }
00248         }
00249     }
00250 }
00251 
00252 static int decode_frame(AVCodecContext *avctx,
00253                         void *data, int *data_size,
00254                         AVPacket *avpkt)
00255 {
00256     const uint8_t *buf = avpkt->data;
00257     int buf_size = avpkt->size;
00258     QpegContext * const a = avctx->priv_data;
00259     AVFrame * p= (AVFrame*)&a->pic;
00260     AVFrame * ref= (AVFrame*)&a->ref;
00261     uint8_t* outdata;
00262     int delta;
00263     const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
00264 
00265     if(ref->data[0])
00266         avctx->release_buffer(avctx, ref);
00267     FFSWAP(AVFrame, *ref, *p);
00268 
00269     p->reference= 3;
00270     if(avctx->get_buffer(avctx, p) < 0){
00271         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00272         return -1;
00273     }
00274     outdata = a->pic.data[0];
00275     if(buf[0x85] == 0x10) {
00276         qpeg_decode_intra(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height);
00277     } else {
00278         delta = buf[0x85];
00279         qpeg_decode_inter(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height, delta, buf + 4, a->ref.data[0]);
00280     }
00281 
00282     /* make the palette available on the way out */
00283     if (pal) {
00284         a->pic.palette_has_changed = 1;
00285         memcpy(a->pal, pal, AVPALETTE_SIZE);
00286     }
00287     memcpy(a->pic.data[1], a->pal, AVPALETTE_SIZE);
00288 
00289     *data_size = sizeof(AVFrame);
00290     *(AVFrame*)data = a->pic;
00291 
00292     return buf_size;
00293 }
00294 
00295 static av_cold int decode_init(AVCodecContext *avctx){
00296     QpegContext * const a = avctx->priv_data;
00297 
00298     avcodec_get_frame_defaults(&a->pic);
00299     avcodec_get_frame_defaults(&a->ref);
00300     a->avctx = avctx;
00301     avctx->pix_fmt= PIX_FMT_PAL8;
00302 
00303     return 0;
00304 }
00305 
00306 static av_cold int decode_end(AVCodecContext *avctx){
00307     QpegContext * const a = avctx->priv_data;
00308     AVFrame * const p= (AVFrame*)&a->pic;
00309     AVFrame * const ref= (AVFrame*)&a->ref;
00310 
00311     if(p->data[0])
00312         avctx->release_buffer(avctx, p);
00313     if(ref->data[0])
00314         avctx->release_buffer(avctx, ref);
00315 
00316     return 0;
00317 }
00318 
00319 AVCodec ff_qpeg_decoder = {
00320     "qpeg",
00321     AVMEDIA_TYPE_VIDEO,
00322     CODEC_ID_QPEG,
00323     sizeof(QpegContext),
00324     decode_init,
00325     NULL,
00326     decode_end,
00327     decode_frame,
00328     CODEC_CAP_DR1,
00329     .long_name = NULL_IF_CONFIG_SMALL("Q-team QPEG"),
00330 };