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 #include "internal.h"
00030 
00031 typedef struct QpegContext{
00032     AVCodecContext *avctx;
00033     AVFrame pic, ref;
00034     uint32_t pal[256];
00035     GetByteContext buffer;
00036 } QpegContext;
00037 
00038 static void qpeg_decode_intra(QpegContext *qctx, uint8_t *dst,
00039                               int stride, int width, int height)
00040 {
00041     int i;
00042     int code;
00043     int c0, c1;
00044     int run, copy;
00045     int filled = 0;
00046     int rows_to_go;
00047 
00048     rows_to_go = height;
00049     height--;
00050     dst = dst + height * stride;
00051 
00052     while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (rows_to_go > 0)) {
00053         code = bytestream2_get_byte(&qctx->buffer);
00054         run = copy = 0;
00055         if(code == 0xFC) /* end-of-picture code */
00056             break;
00057         if(code >= 0xF8) { /* very long run */
00058             c0 = bytestream2_get_byte(&qctx->buffer);
00059             c1 = bytestream2_get_byte(&qctx->buffer);
00060             run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;
00061         } else if (code >= 0xF0) { /* long run */
00062             c0 = bytestream2_get_byte(&qctx->buffer);
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 = bytestream2_get_byte(&qctx->buffer);
00068             c1 = bytestream2_get_byte(&qctx->buffer);
00069             copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;
00070         } else if (code >= 0x80) { /* long copy */
00071             c0 = bytestream2_get_byte(&qctx->buffer);
00072             copy = ((code & 0x7F) << 8) + c0 + 1;
00073         } else { /* short copy */
00074             copy = code + 1;
00075         }
00076 
00077         /* perform actual run or copy */
00078         if(run) {
00079             int p;
00080 
00081             p = bytestream2_get_byte(&qctx->buffer);
00082             for(i = 0; i < run; i++) {
00083                 dst[filled++] = p;
00084                 if (filled >= width) {
00085                     filled = 0;
00086                     dst -= stride;
00087                     rows_to_go--;
00088                     if(rows_to_go <= 0)
00089                         break;
00090                 }
00091             }
00092         } else {
00093             for(i = 0; i < copy; i++) {
00094                 dst[filled++] = bytestream2_get_byte(&qctx->buffer);
00095                 if (filled >= width) {
00096                     filled = 0;
00097                     dst -= stride;
00098                     rows_to_go--;
00099                     if(rows_to_go <= 0)
00100                         break;
00101                 }
00102             }
00103         }
00104     }
00105 }
00106 
00107 static const int qpeg_table_h[16] =
00108  { 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};
00109 static const int qpeg_table_w[16] =
00110  { 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};
00111 
00112 /* Decodes delta frames */
00113 static void qpeg_decode_inter(QpegContext *qctx, uint8_t *dst,
00114                               int stride, int width, int height,
00115                               int delta, const uint8_t *ctable,
00116                               uint8_t *refdata)
00117 {
00118     int i, j;
00119     int code;
00120     int filled = 0;
00121     int orig_height;
00122 
00123     if(!refdata)
00124         refdata= dst;
00125 
00126     /* copy prev frame */
00127     for(i = 0; i < height; i++)
00128         memcpy(dst + (i * stride), refdata + (i * stride), width);
00129 
00130     orig_height = height;
00131     height--;
00132     dst = dst + height * stride;
00133 
00134     while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (height >= 0)) {
00135         code = bytestream2_get_byte(&qctx->buffer);
00136 
00137         if(delta) {
00138             /* motion compensation */
00139             while(bytestream2_get_bytes_left(&qctx->buffer) > 0 && (code & 0xF0) == 0xF0) {
00140                 if(delta == 1) {
00141                     int me_idx;
00142                     int me_w, me_h, me_x, me_y;
00143                     uint8_t *me_plane;
00144                     int corr, val;
00145 
00146                     /* get block size by index */
00147                     me_idx = code & 0xF;
00148                     me_w = qpeg_table_w[me_idx];
00149                     me_h = qpeg_table_h[me_idx];
00150 
00151                     /* extract motion vector */
00152                     corr = bytestream2_get_byte(&qctx->buffer);
00153 
00154                     val = corr >> 4;
00155                     if(val > 7)
00156                         val -= 16;
00157                     me_x = val;
00158 
00159                     val = corr & 0xF;
00160                     if(val > 7)
00161                         val -= 16;
00162                     me_y = val;
00163 
00164                     /* check motion vector */
00165                     if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||
00166                        (height - me_y - me_h < 0) || (height - me_y > orig_height) ||
00167                        (filled + me_w > width) || (height - me_h < 0))
00168                         av_log(NULL, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",
00169                                me_x, me_y, me_w, me_h, filled, height);
00170                     else {
00171                         /* do motion compensation */
00172                         me_plane = refdata + (filled + me_x) + (height - me_y) * stride;
00173                         for(j = 0; j < me_h; j++) {
00174                             for(i = 0; i < me_w; i++)
00175                                 dst[filled + i - (j * stride)] = me_plane[i - (j * stride)];
00176                         }
00177                     }
00178                 }
00179                 code = bytestream2_get_byte(&qctx->buffer);
00180             }
00181         }
00182 
00183         if(code == 0xE0) /* end-of-picture code */
00184             break;
00185         if(code > 0xE0) { /* run code: 0xE1..0xFF */
00186             int p;
00187 
00188             code &= 0x1F;
00189             p = bytestream2_get_byte(&qctx->buffer);
00190             for(i = 0; i <= code; i++) {
00191                 dst[filled++] = p;
00192                 if(filled >= width) {
00193                     filled = 0;
00194                     dst -= stride;
00195                     height--;
00196                     if(height < 0)
00197                         break;
00198                 }
00199             }
00200         } else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */
00201             code &= 0x1F;
00202 
00203             if(code + 1 > bytestream2_get_bytes_left(&qctx->buffer))
00204                 break;
00205 
00206             for(i = 0; i <= code; i++) {
00207                 dst[filled++] = bytestream2_get_byte(&qctx->buffer);
00208                 if(filled >= width) {
00209                     filled = 0;
00210                     dst -= stride;
00211                     height--;
00212                     if(height < 0)
00213                         break;
00214                 }
00215             }
00216         } else if(code >= 0x80) { /* skip code: 0x80..0xBF */
00217             int skip;
00218 
00219             code &= 0x3F;
00220             /* codes 0x80 and 0x81 are actually escape codes,
00221                skip value minus constant is in the next byte */
00222             if(!code)
00223                 skip = bytestream2_get_byte(&qctx->buffer) +  64;
00224             else if(code == 1)
00225                 skip = bytestream2_get_byte(&qctx->buffer) + 320;
00226             else
00227                 skip = code;
00228             filled += skip;
00229             while( filled >= width) {
00230                 filled -= width;
00231                 dst -= stride;
00232                 height--;
00233                 if(height < 0)
00234                     break;
00235             }
00236         } else {
00237             /* zero code treated as one-pixel skip */
00238             if(code) {
00239                 dst[filled++] = ctable[code & 0x7F];
00240             }
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 *got_frame,
00254                         AVPacket *avpkt)
00255 {
00256     uint8_t ctable[128];
00257     QpegContext * const a = avctx->priv_data;
00258     AVFrame *  p = &a->pic;
00259     AVFrame * ref= &a->ref;
00260     uint8_t* outdata;
00261     int delta;
00262     const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
00263 
00264     if (avpkt->size < 0x86) {
00265         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
00266         return AVERROR_INVALIDDATA;
00267     }
00268 
00269     bytestream2_init(&a->buffer, avpkt->data, avpkt->size);
00270 
00271     if(ref->data[0])
00272         avctx->release_buffer(avctx, ref);
00273     FFSWAP(AVFrame, *ref, *p);
00274 
00275     p->reference= 3;
00276     if(ff_get_buffer(avctx, p) < 0){
00277         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00278         return -1;
00279     }
00280     outdata = a->pic.data[0];
00281     bytestream2_skip(&a->buffer, 4);
00282     bytestream2_get_buffer(&a->buffer, ctable, 128);
00283     bytestream2_skip(&a->buffer, 1);
00284 
00285     delta = bytestream2_get_byte(&a->buffer);
00286     if(delta == 0x10) {
00287         qpeg_decode_intra(a, outdata, a->pic.linesize[0], avctx->width, avctx->height);
00288     } else {
00289         qpeg_decode_inter(a, outdata, a->pic.linesize[0], avctx->width, avctx->height, delta, ctable, a->ref.data[0]);
00290     }
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     *got_frame      = 1;
00300     *(AVFrame*)data = a->pic;
00301 
00302     return avpkt->size;
00303 }
00304 
00305 static void decode_flush(AVCodecContext *avctx){
00306     QpegContext * const a = avctx->priv_data;
00307     int i, pal_size;
00308     const uint8_t *pal_src;
00309 
00310     pal_size = FFMIN(1024U, avctx->extradata_size);
00311     pal_src = avctx->extradata + avctx->extradata_size - pal_size;
00312 
00313     for (i=0; i<pal_size/4; i++)
00314         a->pal[i] = 0xFFU<<24 | AV_RL32(pal_src+4*i);
00315 }
00316 
00317 static av_cold int decode_init(AVCodecContext *avctx){
00318     QpegContext * const a = avctx->priv_data;
00319 
00320     avcodec_get_frame_defaults(&a->pic);
00321     avcodec_get_frame_defaults(&a->ref);
00322     a->avctx = avctx;
00323     avctx->pix_fmt= AV_PIX_FMT_PAL8;
00324 
00325     decode_flush(avctx);
00326 
00327     return 0;
00328 }
00329 
00330 static av_cold int decode_end(AVCodecContext *avctx){
00331     QpegContext * const a = avctx->priv_data;
00332     AVFrame * const p = &a->pic;
00333     AVFrame * const ref= &a->ref;
00334 
00335     if(p->data[0])
00336         avctx->release_buffer(avctx, p);
00337     if(ref->data[0])
00338         avctx->release_buffer(avctx, ref);
00339 
00340     return 0;
00341 }
00342 
00343 AVCodec ff_qpeg_decoder = {
00344     .name           = "qpeg",
00345     .type           = AVMEDIA_TYPE_VIDEO,
00346     .id             = AV_CODEC_ID_QPEG,
00347     .priv_data_size = sizeof(QpegContext),
00348     .init           = decode_init,
00349     .close          = decode_end,
00350     .decode         = decode_frame,
00351     .flush          = decode_flush,
00352     .capabilities   = CODEC_CAP_DR1,
00353     .long_name      = NULL_IF_CONFIG_SMALL("Q-team QPEG"),
00354 };