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 #include "bytestream.h"
00029 
00030 typedef struct QpegContext{
00031     AVCodecContext *avctx;
00032     AVFrame pic, ref;
00033     uint32_t pal[256];
00034     GetByteContext buffer;
00035 } QpegContext;
00036 
00037 static void qpeg_decode_intra(QpegContext *qctx, uint8_t *dst,
00038                               int stride, int width, int height)
00039 {
00040     int i;
00041     int code;
00042     int c0, c1;
00043     int run, copy;
00044     int filled = 0;
00045     int rows_to_go;
00046 
00047     rows_to_go = height;
00048     height--;
00049     dst = dst + height * stride;
00050 
00051     while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (rows_to_go > 0)) {
00052         code = bytestream2_get_byte(&qctx->buffer);
00053         run = copy = 0;
00054         if(code == 0xFC) /* end-of-picture code */
00055             break;
00056         if(code >= 0xF8) { /* very long run */
00057             c0 = bytestream2_get_byte(&qctx->buffer);
00058             c1 = bytestream2_get_byte(&qctx->buffer);
00059             run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;
00060         } else if (code >= 0xF0) { /* long run */
00061             c0 = bytestream2_get_byte(&qctx->buffer);
00062             run = ((code & 0xF) << 8) + c0 + 2;
00063         } else if (code >= 0xE0) { /* short run */
00064             run = (code & 0x1F) + 2;
00065         } else if (code >= 0xC0) { /* very long copy */
00066             c0 = bytestream2_get_byte(&qctx->buffer);
00067             c1 = bytestream2_get_byte(&qctx->buffer);
00068             copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;
00069         } else if (code >= 0x80) { /* long copy */
00070             c0 = bytestream2_get_byte(&qctx->buffer);
00071             copy = ((code & 0x7F) << 8) + c0 + 1;
00072         } else { /* short copy */
00073             copy = code + 1;
00074         }
00075 
00076         /* perform actual run or copy */
00077         if(run) {
00078             int p;
00079 
00080             p = bytestream2_get_byte(&qctx->buffer);
00081             for(i = 0; i < run; i++) {
00082                 dst[filled++] = p;
00083                 if (filled >= width) {
00084                     filled = 0;
00085                     dst -= stride;
00086                     rows_to_go--;
00087                     if(rows_to_go <= 0)
00088                         break;
00089                 }
00090             }
00091         } else {
00092             for(i = 0; i < copy; i++) {
00093                 dst[filled++] = bytestream2_get_byte(&qctx->buffer);
00094                 if (filled >= width) {
00095                     filled = 0;
00096                     dst -= stride;
00097                     rows_to_go--;
00098                     if(rows_to_go <= 0)
00099                         break;
00100                 }
00101             }
00102         }
00103     }
00104 }
00105 
00106 static const int qpeg_table_h[16] =
00107  { 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};
00108 static const int qpeg_table_w[16] =
00109  { 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};
00110 
00111 /* Decodes delta frames */
00112 static void qpeg_decode_inter(QpegContext *qctx, uint8_t *dst,
00113                               int stride, int width, int height,
00114                               int delta, const uint8_t *ctable,
00115                               uint8_t *refdata)
00116 {
00117     int i, j;
00118     int code;
00119     int filled = 0;
00120     int orig_height;
00121 
00122     if(!refdata)
00123         refdata= dst;
00124 
00125     /* copy prev frame */
00126     for(i = 0; i < height; i++)
00127         memcpy(dst + (i * stride), refdata + (i * stride), width);
00128 
00129     orig_height = height;
00130     height--;
00131     dst = dst + height * stride;
00132 
00133     while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (height >= 0)) {
00134         code = bytestream2_get_byte(&qctx->buffer);
00135 
00136         if(delta) {
00137             /* motion compensation */
00138             while(bytestream2_get_bytes_left(&qctx->buffer) > 0 && (code & 0xF0) == 0xF0) {
00139                 if(delta == 1) {
00140                     int me_idx;
00141                     int me_w, me_h, me_x, me_y;
00142                     uint8_t *me_plane;
00143                     int corr, val;
00144 
00145                     /* get block size by index */
00146                     me_idx = code & 0xF;
00147                     me_w = qpeg_table_w[me_idx];
00148                     me_h = qpeg_table_h[me_idx];
00149 
00150                     /* extract motion vector */
00151                     corr = bytestream2_get_byte(&qctx->buffer);
00152 
00153                     val = corr >> 4;
00154                     if(val > 7)
00155                         val -= 16;
00156                     me_x = val;
00157 
00158                     val = corr & 0xF;
00159                     if(val > 7)
00160                         val -= 16;
00161                     me_y = val;
00162 
00163                     /* check motion vector */
00164                     if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||
00165                        (height - me_y - me_h < 0) || (height - me_y > orig_height) ||
00166                        (filled + me_w > width) || (height - me_h < 0))
00167                         av_log(NULL, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",
00168                                me_x, me_y, me_w, me_h, filled, height);
00169                     else {
00170                         /* do motion compensation */
00171                         me_plane = refdata + (filled + me_x) + (height - me_y) * stride;
00172                         for(j = 0; j < me_h; j++) {
00173                             for(i = 0; i < me_w; i++)
00174                                 dst[filled + i - (j * stride)] = me_plane[i - (j * stride)];
00175                         }
00176                     }
00177                 }
00178                 code = bytestream2_get_byte(&qctx->buffer);
00179             }
00180         }
00181 
00182         if(code == 0xE0) /* end-of-picture code */
00183             break;
00184         if(code > 0xE0) { /* run code: 0xE1..0xFF */
00185             int p;
00186 
00187             code &= 0x1F;
00188             p = bytestream2_get_byte(&qctx->buffer);
00189             for(i = 0; i <= code; i++) {
00190                 dst[filled++] = p;
00191                 if(filled >= width) {
00192                     filled = 0;
00193                     dst -= stride;
00194                     height--;
00195                     if(height < 0)
00196                         break;
00197                 }
00198             }
00199         } else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */
00200             code &= 0x1F;
00201 
00202             if(code + 1 > bytestream2_get_bytes_left(&qctx->buffer))
00203                 break;
00204 
00205             for(i = 0; i <= code; i++) {
00206                 dst[filled++] = bytestream2_get_byte(&qctx->buffer);
00207                 if(filled >= width) {
00208                     filled = 0;
00209                     dst -= stride;
00210                     height--;
00211                     if(height < 0)
00212                         break;
00213                 }
00214             }
00215         } else if(code >= 0x80) { /* skip code: 0x80..0xBF */
00216             int skip;
00217 
00218             code &= 0x3F;
00219             /* codes 0x80 and 0x81 are actually escape codes,
00220                skip value minus constant is in the next byte */
00221             if(!code)
00222                 skip = bytestream2_get_byte(&qctx->buffer) +  64;
00223             else if(code == 1)
00224                 skip = bytestream2_get_byte(&qctx->buffer) + 320;
00225             else
00226                 skip = code;
00227             filled += skip;
00228             while( filled >= width) {
00229                 filled -= width;
00230                 dst -= stride;
00231                 height--;
00232                 if(height < 0)
00233                     break;
00234             }
00235         } else {
00236             /* zero code treated as one-pixel skip */
00237             if(code) {
00238                 dst[filled++] = ctable[code & 0x7F];
00239             }
00240             else
00241                 filled++;
00242             if(filled >= width) {
00243                 filled = 0;
00244                 dst -= stride;
00245                 height--;
00246             }
00247         }
00248     }
00249 }
00250 
00251 static int decode_frame(AVCodecContext *avctx,
00252                         void *data, int *data_size,
00253                         AVPacket *avpkt)
00254 {
00255     uint8_t ctable[128];
00256     QpegContext * const a = avctx->priv_data;
00257     AVFrame *  p = &a->pic;
00258     AVFrame * ref= &a->ref;
00259     uint8_t* outdata;
00260     int delta;
00261     const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
00262 
00263     if (avpkt->size < 0x86) {
00264         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
00265         return AVERROR_INVALIDDATA;
00266     }
00267 
00268     bytestream2_init(&a->buffer, avpkt->data, avpkt->size);
00269 
00270     if(ref->data[0])
00271         avctx->release_buffer(avctx, ref);
00272     FFSWAP(AVFrame, *ref, *p);
00273 
00274     p->reference= 3;
00275     if(avctx->get_buffer(avctx, p) < 0){
00276         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00277         return -1;
00278     }
00279     outdata = a->pic.data[0];
00280     bytestream2_skip(&a->buffer, 4);
00281     bytestream2_get_buffer(&a->buffer, ctable, 128);
00282     bytestream2_skip(&a->buffer, 1);
00283 
00284     delta = bytestream2_get_byte(&a->buffer);
00285     if(delta == 0x10) {
00286         qpeg_decode_intra(a, outdata, a->pic.linesize[0], avctx->width, avctx->height);
00287     } else {
00288         qpeg_decode_inter(a, outdata, a->pic.linesize[0], avctx->width, avctx->height, delta, ctable, a->ref.data[0]);
00289     }
00290 
00291     /* make the palette available on the way out */
00292     if (pal) {
00293         a->pic.palette_has_changed = 1;
00294         memcpy(a->pal, pal, AVPALETTE_SIZE);
00295     }
00296     memcpy(a->pic.data[1], a->pal, AVPALETTE_SIZE);
00297 
00298     *data_size = sizeof(AVFrame);
00299     *(AVFrame*)data = a->pic;
00300 
00301     return avpkt->size;
00302 }
00303 
00304 static av_cold int decode_init(AVCodecContext *avctx){
00305     QpegContext * const a = avctx->priv_data;
00306 
00307     avcodec_get_frame_defaults(&a->pic);
00308     avcodec_get_frame_defaults(&a->ref);
00309     a->avctx = avctx;
00310     avctx->pix_fmt= PIX_FMT_PAL8;
00311 
00312     return 0;
00313 }
00314 
00315 static av_cold int decode_end(AVCodecContext *avctx){
00316     QpegContext * const a = avctx->priv_data;
00317     AVFrame * const p = &a->pic;
00318     AVFrame * const ref= &a->ref;
00319 
00320     if(p->data[0])
00321         avctx->release_buffer(avctx, p);
00322     if(ref->data[0])
00323         avctx->release_buffer(avctx, ref);
00324 
00325     return 0;
00326 }
00327 
00328 AVCodec ff_qpeg_decoder = {
00329     .name           = "qpeg",
00330     .type           = AVMEDIA_TYPE_VIDEO,
00331     .id             = CODEC_ID_QPEG,
00332     .priv_data_size = sizeof(QpegContext),
00333     .init           = decode_init,
00334     .close          = decode_end,
00335     .decode         = decode_frame,
00336     .capabilities   = CODEC_CAP_DR1,
00337     .long_name      = NULL_IF_CONFIG_SMALL("Q-team QPEG"),
00338 };