Libav 0.7.1
libavcodec/dfa.c
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00001 /*
00002  * Chronomaster DFA Video Decoder
00003  * Copyright (c) 2011 Konstantin Shishkov
00004  * based on work by Vladimir "VAG" Gneushev
00005  *
00006  * This file is part of Libav.
00007  *
00008  * Libav is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * Libav is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with Libav; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00023 #include "avcodec.h"
00024 #include "libavutil/intreadwrite.h"
00025 #include "bytestream.h"
00026 #include "libavutil/lzo.h" // for av_memcpy_backptr
00027 
00028 typedef struct DfaContext {
00029     AVFrame pic;
00030 
00031     uint32_t pal[256];
00032     uint8_t *frame_buf;
00033 } DfaContext;
00034 
00035 static av_cold int dfa_decode_init(AVCodecContext *avctx)
00036 {
00037     DfaContext *s = avctx->priv_data;
00038 
00039     avctx->pix_fmt = PIX_FMT_PAL8;
00040 
00041     s->frame_buf = av_mallocz(avctx->width * avctx->height + AV_LZO_OUTPUT_PADDING);
00042     if (!s->frame_buf)
00043         return AVERROR(ENOMEM);
00044 
00045     return 0;
00046 }
00047 
00048 static int decode_copy(uint8_t *frame, int width, int height,
00049                        const uint8_t *src, const uint8_t *src_end)
00050 {
00051     const int size = width * height;
00052 
00053     if (src_end - src < size)
00054         return -1;
00055     bytestream_get_buffer(&src, frame, size);
00056     return 0;
00057 }
00058 
00059 static int decode_tsw1(uint8_t *frame, int width, int height,
00060                        const uint8_t *src, const uint8_t *src_end)
00061 {
00062     const uint8_t *frame_start = frame;
00063     const uint8_t *frame_end   = frame + width * height;
00064     int mask = 0x10000, bitbuf = 0;
00065     int v, count, segments;
00066     unsigned offset;
00067 
00068     segments = bytestream_get_le32(&src);
00069     offset   = bytestream_get_le32(&src);
00070     if (frame_end - frame <= offset)
00071         return -1;
00072     frame += offset;
00073     while (segments--) {
00074         if (mask == 0x10000) {
00075             if (src >= src_end)
00076                 return -1;
00077             bitbuf = bytestream_get_le16(&src);
00078             mask = 1;
00079         }
00080         if (src_end - src < 2 || frame_end - frame < 2)
00081             return -1;
00082         if (bitbuf & mask) {
00083             v = bytestream_get_le16(&src);
00084             offset = (v & 0x1FFF) << 1;
00085             count = ((v >> 13) + 2) << 1;
00086             if (frame - frame_start < offset || frame_end - frame < count)
00087                 return -1;
00088             av_memcpy_backptr(frame, offset, count);
00089             frame += count;
00090         } else {
00091             *frame++ = *src++;
00092             *frame++ = *src++;
00093         }
00094         mask <<= 1;
00095     }
00096 
00097     return 0;
00098 }
00099 
00100 static int decode_dsw1(uint8_t *frame, int width, int height,
00101                        const uint8_t *src, const uint8_t *src_end)
00102 {
00103     const uint8_t *frame_start = frame;
00104     const uint8_t *frame_end   = frame + width * height;
00105     int mask = 0x10000, bitbuf = 0;
00106     int v, offset, count, segments;
00107 
00108     segments = bytestream_get_le16(&src);
00109     while (segments--) {
00110         if (mask == 0x10000) {
00111             if (src >= src_end)
00112                 return -1;
00113             bitbuf = bytestream_get_le16(&src);
00114             mask = 1;
00115         }
00116         if (src_end - src < 2 || frame_end - frame < 2)
00117             return -1;
00118         if (bitbuf & mask) {
00119             v = bytestream_get_le16(&src);
00120             offset = (v & 0x1FFF) << 1;
00121             count = ((v >> 13) + 2) << 1;
00122             if (frame - frame_start < offset || frame_end - frame < count)
00123                 return -1;
00124             // can't use av_memcpy_backptr() since it can overwrite following pixels
00125             for (v = 0; v < count; v++)
00126                 frame[v] = frame[v - offset];
00127             frame += count;
00128         } else if (bitbuf & (mask << 1)) {
00129             frame += bytestream_get_le16(&src);
00130         } else {
00131             *frame++ = *src++;
00132             *frame++ = *src++;
00133         }
00134         mask <<= 2;
00135     }
00136 
00137     return 0;
00138 }
00139 
00140 static int decode_dds1(uint8_t *frame, int width, int height,
00141                        const uint8_t *src, const uint8_t *src_end)
00142 {
00143     const uint8_t *frame_start = frame;
00144     const uint8_t *frame_end   = frame + width * height;
00145     int mask = 0x10000, bitbuf = 0;
00146     int i, v, offset, count, segments;
00147 
00148     segments = bytestream_get_le16(&src);
00149     while (segments--) {
00150         if (mask == 0x10000) {
00151             if (src >= src_end)
00152                 return -1;
00153             bitbuf = bytestream_get_le16(&src);
00154             mask = 1;
00155         }
00156         if (src_end - src < 2 || frame_end - frame < width + 2)
00157             return -1;
00158         if (bitbuf & mask) {
00159             v = bytestream_get_le16(&src);
00160             offset = (v & 0x1FFF) << 2;
00161             count = ((v >> 13) + 2) << 1;
00162             if (frame - frame_start < offset || frame_end - frame < count*2 + width)
00163                 return -1;
00164             for (i = 0; i < count; i++) {
00165                 frame[0] = frame[1] =
00166                 frame[width] = frame[width + 1] = frame[-offset];
00167 
00168                 frame += 2;
00169             }
00170         } else if (bitbuf & (mask << 1)) {
00171             frame += bytestream_get_le16(&src) * 2;
00172         } else {
00173             frame[0] = frame[1] =
00174             frame[width] = frame[width + 1] =  *src++;
00175             frame += 2;
00176             frame[0] = frame[1] =
00177             frame[width] = frame[width + 1] =  *src++;
00178             frame += 2;
00179         }
00180         mask <<= 2;
00181     }
00182 
00183     return 0;
00184 }
00185 
00186 static int decode_bdlt(uint8_t *frame, int width, int height,
00187                        const uint8_t *src, const uint8_t *src_end)
00188 {
00189     uint8_t *line_ptr;
00190     int count, lines, segments;
00191 
00192     count = bytestream_get_le16(&src);
00193     if (count >= height)
00194         return -1;
00195     frame += width * count;
00196     lines = bytestream_get_le16(&src);
00197     if (count + lines > height || src >= src_end)
00198         return -1;
00199 
00200     while (lines--) {
00201         line_ptr = frame;
00202         frame += width;
00203         segments = *src++;
00204         while (segments--) {
00205             if (src_end - src < 3)
00206                 return -1;
00207             if (frame - line_ptr <= *src)
00208                 return -1;
00209             line_ptr += *src++;
00210             count = (int8_t)*src++;
00211             if (count >= 0) {
00212                 if (frame - line_ptr < count || src_end - src < count)
00213                     return -1;
00214                 bytestream_get_buffer(&src, line_ptr, count);
00215             } else {
00216                 count = -count;
00217                 if (frame - line_ptr < count || src >= src_end)
00218                     return -1;
00219                 memset(line_ptr, *src++, count);
00220             }
00221             line_ptr += count;
00222         }
00223     }
00224 
00225     return 0;
00226 }
00227 
00228 static int decode_wdlt(uint8_t *frame, int width, int height,
00229                        const uint8_t *src, const uint8_t *src_end)
00230 {
00231     const uint8_t *frame_end   = frame + width * height;
00232     uint8_t *line_ptr;
00233     int count, i, v, lines, segments;
00234 
00235     lines = bytestream_get_le16(&src);
00236     if (lines > height || src >= src_end)
00237         return -1;
00238 
00239     while (lines--) {
00240         segments = bytestream_get_le16(&src);
00241         while ((segments & 0xC000) == 0xC000) {
00242             unsigned delta = -((int16_t)segments * width);
00243             if (frame_end - frame <= delta)
00244                 return -1;
00245             frame    += delta;
00246             segments = bytestream_get_le16(&src);
00247         }
00248         if (frame_end <= frame)
00249             return -1;
00250         if (segments & 0x8000) {
00251             frame[width - 1] = segments & 0xFF;
00252             segments = bytestream_get_le16(&src);
00253         }
00254         line_ptr = frame;
00255         frame += width;
00256         while (segments--) {
00257             if (src_end - src < 2)
00258                 return -1;
00259             if (frame - line_ptr <= *src)
00260                 return -1;
00261             line_ptr += *src++;
00262             count = (int8_t)*src++;
00263             if (count >= 0) {
00264                 if (frame - line_ptr < count*2 || src_end - src < count*2)
00265                     return -1;
00266                 bytestream_get_buffer(&src, line_ptr, count*2);
00267                 line_ptr += count * 2;
00268             } else {
00269                 count = -count;
00270                 if (frame - line_ptr < count*2 || src_end - src < 2)
00271                     return -1;
00272                 v = bytestream_get_le16(&src);
00273                 for (i = 0; i < count; i++)
00274                     bytestream_put_le16(&line_ptr, v);
00275             }
00276         }
00277     }
00278 
00279     return 0;
00280 }
00281 
00282 static int decode_unk6(uint8_t *frame, int width, int height,
00283                        const uint8_t *src, const uint8_t *src_end)
00284 {
00285     return -1;
00286 }
00287 
00288 static int decode_blck(uint8_t *frame, int width, int height,
00289                        const uint8_t *src, const uint8_t *src_end)
00290 {
00291     memset(frame, 0, width * height);
00292     return 0;
00293 }
00294 
00295 
00296 typedef int (*chunk_decoder)(uint8_t *frame, int width, int height,
00297                              const uint8_t *src, const uint8_t *src_end);
00298 
00299 static const chunk_decoder decoder[8] = {
00300     decode_copy, decode_tsw1, decode_bdlt, decode_wdlt,
00301     decode_unk6, decode_dsw1, decode_blck, decode_dds1,
00302 };
00303 
00304 static const char* chunk_name[8] = {
00305     "COPY", "TSW1", "BDLT", "WDLT", "????", "DSW1", "BLCK", "DDS1"
00306 };
00307 
00308 static int dfa_decode_frame(AVCodecContext *avctx,
00309                             void *data, int *data_size,
00310                             AVPacket *avpkt)
00311 {
00312     DfaContext *s = avctx->priv_data;
00313     const uint8_t *buf = avpkt->data;
00314     const uint8_t *buf_end = avpkt->data + avpkt->size;
00315     const uint8_t *tmp_buf;
00316     uint32_t chunk_type, chunk_size;
00317     uint8_t *dst;
00318     int ret;
00319     int i, pal_elems;
00320 
00321     if (s->pic.data[0])
00322         avctx->release_buffer(avctx, &s->pic);
00323 
00324     if ((ret = avctx->get_buffer(avctx, &s->pic))) {
00325         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00326         return ret;
00327     }
00328 
00329     while (buf < buf_end) {
00330         chunk_size = AV_RL32(buf + 4);
00331         chunk_type = AV_RL32(buf + 8);
00332         buf += 12;
00333         if (buf_end - buf < chunk_size) {
00334             av_log(avctx, AV_LOG_ERROR, "Chunk size is too big (%d bytes)\n", chunk_size);
00335             return -1;
00336         }
00337         if (!chunk_type)
00338             break;
00339         if (chunk_type == 1) {
00340             pal_elems = FFMIN(chunk_size / 3, 256);
00341             tmp_buf = buf;
00342             for (i = 0; i < pal_elems; i++) {
00343                 s->pal[i] = bytestream_get_be24(&tmp_buf) << 2;
00344                 s->pal[i] |= (s->pal[i] >> 6) & 0x333;
00345             }
00346             s->pic.palette_has_changed = 1;
00347         } else if (chunk_type <= 9) {
00348             if (decoder[chunk_type - 2](s->frame_buf, avctx->width, avctx->height,
00349                                         buf, buf + chunk_size)) {
00350                 av_log(avctx, AV_LOG_ERROR, "Error decoding %s chunk\n",
00351                        chunk_name[chunk_type - 2]);
00352                 return -1;
00353             }
00354         } else {
00355             av_log(avctx, AV_LOG_WARNING, "Ignoring unknown chunk type %d\n",
00356                    chunk_type);
00357         }
00358         buf += chunk_size;
00359     }
00360 
00361     buf = s->frame_buf;
00362     dst = s->pic.data[0];
00363     for (i = 0; i < avctx->height; i++) {
00364         memcpy(dst, buf, avctx->width);
00365         dst += s->pic.linesize[0];
00366         buf += avctx->width;
00367     }
00368     memcpy(s->pic.data[1], s->pal, sizeof(s->pal));
00369 
00370     *data_size = sizeof(AVFrame);
00371     *(AVFrame*)data = s->pic;
00372 
00373     return avpkt->size;
00374 }
00375 
00376 static av_cold int dfa_decode_end(AVCodecContext *avctx)
00377 {
00378     DfaContext *s = avctx->priv_data;
00379 
00380     if (s->pic.data[0])
00381         avctx->release_buffer(avctx, &s->pic);
00382 
00383     av_freep(&s->frame_buf);
00384 
00385     return 0;
00386 }
00387 
00388 AVCodec ff_dfa_decoder = {
00389     "dfa",
00390     AVMEDIA_TYPE_VIDEO,
00391     CODEC_ID_DFA,
00392     sizeof(DfaContext),
00393     dfa_decode_init,
00394     NULL,
00395     dfa_decode_end,
00396     dfa_decode_frame,
00397     CODEC_CAP_DR1,
00398     .long_name = NULL_IF_CONFIG_SMALL("Chronomaster DFA"),
00399 };