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libavcodec/xxan.c

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00001 /*
00002  * Wing Commander/Xan Video Decoder
00003  * Copyright (C) 2011 Konstantin Shishkov
00004  * based on work by Mike Melanson
00005  *
00006  * This file is part of FFmpeg.
00007  *
00008  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 #define BITSTREAM_READER_LE
00027 #include "get_bits.h"
00028 // for av_memcpy_backptr
00029 #include "libavutil/lzo.h"
00030 
00031 typedef struct XanContext {
00032     AVCodecContext *avctx;
00033     AVFrame pic;
00034 
00035     uint8_t *y_buffer;
00036     uint8_t *scratch_buffer;
00037     int     buffer_size;
00038     GetByteContext gb;
00039 } XanContext;
00040 
00041 static av_cold int xan_decode_init(AVCodecContext *avctx)
00042 {
00043     XanContext *s = avctx->priv_data;
00044 
00045     s->avctx = avctx;
00046 
00047     avctx->pix_fmt = PIX_FMT_YUV420P;
00048 
00049     s->buffer_size = avctx->width * avctx->height;
00050     s->y_buffer = av_malloc(s->buffer_size);
00051     if (!s->y_buffer)
00052         return AVERROR(ENOMEM);
00053     s->scratch_buffer = av_malloc(s->buffer_size + 130);
00054     if (!s->scratch_buffer) {
00055         av_freep(&s->y_buffer);
00056         return AVERROR(ENOMEM);
00057     }
00058 
00059     return 0;
00060 }
00061 
00062 static int xan_unpack_luma(XanContext *s,
00063                            uint8_t *dst, const int dst_size)
00064 {
00065    int tree_size, eof;
00066    int bits, mask;
00067    int tree_root, node;
00068    const uint8_t *dst_end = dst + dst_size;
00069    GetByteContext tree = s->gb;
00070    int start_off = bytestream2_tell(&tree);
00071 
00072    tree_size = bytestream2_get_byte(&s->gb);
00073    eof       = bytestream2_get_byte(&s->gb);
00074    tree_root = eof + tree_size;
00075    bytestream2_skip(&s->gb, tree_size * 2);
00076 
00077    node = tree_root;
00078    bits = bytestream2_get_byte(&s->gb);
00079    mask = 0x80;
00080    for (;;) {
00081        int bit = !!(bits & mask);
00082        mask >>= 1;
00083        bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);
00084        node = bytestream2_get_byte(&tree);
00085        if (node == eof)
00086            break;
00087        if (node < eof) {
00088            *dst++ = node;
00089            if (dst > dst_end)
00090                break;
00091            node = tree_root;
00092        }
00093        if (!mask) {
00094            if (bytestream2_get_bytes_left(&s->gb) <= 0)
00095                break;
00096            bits = bytestream2_get_byteu(&s->gb);
00097            mask = 0x80;
00098        }
00099    }
00100    return dst != dst_end ? AVERROR_INVALIDDATA : 0;
00101 }
00102 
00103 /* almost the same as in xan_wc3 decoder */
00104 static int xan_unpack(XanContext *s,
00105                       uint8_t *dest, const int dest_len)
00106 {
00107     uint8_t opcode;
00108     int size;
00109     uint8_t *orig_dest = dest;
00110     const uint8_t *dest_end = dest + dest_len;
00111 
00112     while (dest < dest_end) {
00113         if (bytestream2_get_bytes_left(&s->gb) <= 0)
00114             return AVERROR_INVALIDDATA;
00115 
00116         opcode = bytestream2_get_byteu(&s->gb);
00117 
00118         if (opcode < 0xe0) {
00119             int size2, back;
00120             if ((opcode & 0x80) == 0) {
00121                 size  = opcode & 3;
00122                 back  = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;
00123                 size2 = ((opcode & 0x1c) >> 2) + 3;
00124             } else if ((opcode & 0x40) == 0) {
00125                 size  = bytestream2_peek_byte(&s->gb) >> 6;
00126                 back  = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;
00127                 size2 = (opcode & 0x3f) + 4;
00128             } else {
00129                 size  = opcode & 3;
00130                 back  = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;
00131                 size2 = ((opcode & 0x0c) <<  6) + bytestream2_get_byte(&s->gb) + 5;
00132                 if (size + size2 > dest_end - dest)
00133                     break;
00134             }
00135             if (dest + size + size2 > dest_end ||
00136                 dest - orig_dest + size < back)
00137                 return -1;
00138             bytestream2_get_buffer(&s->gb, dest, size);
00139             dest += size;
00140             av_memcpy_backptr(dest, back, size2);
00141             dest += size2;
00142         } else {
00143             int finish = opcode >= 0xfc;
00144 
00145             size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
00146             if (dest_end - dest < size)
00147                 return -1;
00148             bytestream2_get_buffer(&s->gb, dest, size);
00149             dest += size;
00150             if (finish)
00151                 break;
00152         }
00153     }
00154     return dest - orig_dest;
00155 }
00156 
00157 static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)
00158 {
00159     XanContext *s = avctx->priv_data;
00160     uint8_t *U, *V;
00161     int val, uval, vval;
00162     int i, j;
00163     const uint8_t *src, *src_end;
00164     const uint8_t *table;
00165     int mode, offset, dec_size, table_size;
00166 
00167     if (!chroma_off)
00168         return 0;
00169     if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {
00170         av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
00171         return -1;
00172     }
00173     bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);
00174     mode        = bytestream2_get_le16(&s->gb);
00175     table       = s->gb.buffer;
00176     table_size  = bytestream2_get_le16(&s->gb);
00177     offset      = table_size * 2;
00178     table_size += 1;
00179 
00180     if (offset >= bytestream2_get_bytes_left(&s->gb)) {
00181         av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
00182         return -1;
00183     }
00184 
00185     bytestream2_skip(&s->gb, offset);
00186     memset(s->scratch_buffer, 0, s->buffer_size);
00187     dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
00188     if (dec_size < 0) {
00189         av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
00190         return -1;
00191     }
00192 
00193     U = s->pic.data[1];
00194     V = s->pic.data[2];
00195     src     = s->scratch_buffer;
00196     src_end = src + dec_size;
00197     if (mode) {
00198         for (j = 0; j < avctx->height >> 1; j++) {
00199             for (i = 0; i < avctx->width >> 1; i++) {
00200                 if (src_end - src < 1)
00201                     return 0;
00202                 val = *src++;
00203                 if (val && val < table_size) {
00204                     val  = AV_RL16(table + (val << 1));
00205                     uval = (val >> 3) & 0xF8;
00206                     vval = (val >> 8) & 0xF8;
00207                     U[i] = uval | (uval >> 5);
00208                     V[i] = vval | (vval >> 5);
00209                 }
00210             }
00211             U += s->pic.linesize[1];
00212             V += s->pic.linesize[2];
00213         }
00214     } else {
00215         uint8_t *U2 = U + s->pic.linesize[1];
00216         uint8_t *V2 = V + s->pic.linesize[2];
00217 
00218         for (j = 0; j < avctx->height >> 2; j++) {
00219             for (i = 0; i < avctx->width >> 1; i += 2) {
00220                 if (src_end - src < 1)
00221                     return 0;
00222                 val = *src++;
00223                 if (val && val < table_size) {
00224                     val  = AV_RL16(table + (val << 1));
00225                     uval = (val >> 3) & 0xF8;
00226                     vval = (val >> 8) & 0xF8;
00227                     U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
00228                     V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
00229                 }
00230             }
00231             U  += s->pic.linesize[1] * 2;
00232             V  += s->pic.linesize[2] * 2;
00233             U2 += s->pic.linesize[1] * 2;
00234             V2 += s->pic.linesize[2] * 2;
00235         }
00236     }
00237 
00238     return 0;
00239 }
00240 
00241 static int xan_decode_frame_type0(AVCodecContext *avctx)
00242 {
00243     XanContext *s = avctx->priv_data;
00244     uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
00245     unsigned  chroma_off, corr_off;
00246     int cur, last;
00247     int i, j;
00248     int ret;
00249 
00250     chroma_off = bytestream2_get_le32(&s->gb);
00251     corr_off   = bytestream2_get_le32(&s->gb);
00252 
00253     if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)
00254         return ret;
00255 
00256     if (corr_off >= (s->gb.buffer_end - s->gb.buffer_start)) {
00257         av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
00258         corr_off = 0;
00259     }
00260     bytestream2_seek(&s->gb, 12, SEEK_SET);
00261     ret = xan_unpack_luma(s, src, s->buffer_size >> 1);
00262     if (ret) {
00263         av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
00264         return ret;
00265     }
00266 
00267     ybuf = s->y_buffer;
00268     last = *src++;
00269     ybuf[0] = last << 1;
00270     for (j = 1; j < avctx->width - 1; j += 2) {
00271         cur = (last + *src++) & 0x1F;
00272         ybuf[j]   = last + cur;
00273         ybuf[j+1] = cur << 1;
00274         last = cur;
00275     }
00276     ybuf[j]  = last << 1;
00277     prev_buf = ybuf;
00278     ybuf += avctx->width;
00279 
00280     for (i = 1; i < avctx->height; i++) {
00281         last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
00282         ybuf[0] = last << 1;
00283         for (j = 1; j < avctx->width - 1; j += 2) {
00284             cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
00285             ybuf[j]   = last + cur;
00286             ybuf[j+1] = cur << 1;
00287             last = cur;
00288         }
00289         ybuf[j] = last << 1;
00290         prev_buf = ybuf;
00291         ybuf += avctx->width;
00292     }
00293 
00294     if (corr_off) {
00295         int corr_end, dec_size;
00296 
00297         corr_end = (s->gb.buffer_end - s->gb.buffer_start);
00298         if (chroma_off > corr_off)
00299             corr_end = chroma_off;
00300         bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
00301         dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
00302         if (dec_size < 0)
00303             dec_size = 0;
00304         else
00305             dec_size = FFMIN(dec_size, s->buffer_size/2 - 1);
00306 
00307         for (i = 0; i < dec_size; i++)
00308             s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
00309     }
00310 
00311     src  = s->y_buffer;
00312     ybuf = s->pic.data[0];
00313     for (j = 0; j < avctx->height; j++) {
00314         for (i = 0; i < avctx->width; i++)
00315             ybuf[i] = (src[i] << 2) | (src[i] >> 3);
00316         src  += avctx->width;
00317         ybuf += s->pic.linesize[0];
00318     }
00319 
00320     return 0;
00321 }
00322 
00323 static int xan_decode_frame_type1(AVCodecContext *avctx)
00324 {
00325     XanContext *s = avctx->priv_data;
00326     uint8_t *ybuf, *src = s->scratch_buffer;
00327     int cur, last;
00328     int i, j;
00329     int ret;
00330 
00331     if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0)
00332         return ret;
00333 
00334     bytestream2_seek(&s->gb, 16, SEEK_SET);
00335     ret = xan_unpack_luma(s, src,
00336                           s->buffer_size >> 1);
00337     if (ret) {
00338         av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
00339         return ret;
00340     }
00341 
00342     ybuf = s->y_buffer;
00343     for (i = 0; i < avctx->height; i++) {
00344         last = (ybuf[0] + (*src++ << 1)) & 0x3F;
00345         ybuf[0] = last;
00346         for (j = 1; j < avctx->width - 1; j += 2) {
00347             cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
00348             ybuf[j]   = (last + cur) >> 1;
00349             ybuf[j+1] = cur;
00350             last = cur;
00351         }
00352         ybuf[j] = last;
00353         ybuf += avctx->width;
00354     }
00355 
00356     src = s->y_buffer;
00357     ybuf = s->pic.data[0];
00358     for (j = 0; j < avctx->height; j++) {
00359         for (i = 0; i < avctx->width; i++)
00360             ybuf[i] = (src[i] << 2) | (src[i] >> 3);
00361         src  += avctx->width;
00362         ybuf += s->pic.linesize[0];
00363     }
00364 
00365     return 0;
00366 }
00367 
00368 static int xan_decode_frame(AVCodecContext *avctx,
00369                             void *data, int *data_size,
00370                             AVPacket *avpkt)
00371 {
00372     XanContext *s = avctx->priv_data;
00373     int ftype;
00374     int ret;
00375 
00376     s->pic.reference = 3;
00377     s->pic.buffer_hints = FF_BUFFER_HINTS_VALID |
00378                           FF_BUFFER_HINTS_PRESERVE |
00379                           FF_BUFFER_HINTS_REUSABLE;
00380     if ((ret = avctx->reget_buffer(avctx, &s->pic))) {
00381         av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
00382         return ret;
00383     }
00384 
00385     bytestream2_init(&s->gb, avpkt->data, avpkt->size);
00386     ftype = bytestream2_get_le32(&s->gb);
00387     switch (ftype) {
00388     case 0:
00389         ret = xan_decode_frame_type0(avctx);
00390         break;
00391     case 1:
00392         ret = xan_decode_frame_type1(avctx);
00393         break;
00394     default:
00395         av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
00396         return -1;
00397     }
00398     if (ret)
00399         return ret;
00400 
00401     *data_size = sizeof(AVFrame);
00402     *(AVFrame*)data = s->pic;
00403 
00404     return avpkt->size;
00405 }
00406 
00407 static av_cold int xan_decode_end(AVCodecContext *avctx)
00408 {
00409     XanContext *s = avctx->priv_data;
00410 
00411     if (s->pic.data[0])
00412         avctx->release_buffer(avctx, &s->pic);
00413 
00414     av_freep(&s->y_buffer);
00415     av_freep(&s->scratch_buffer);
00416 
00417     return 0;
00418 }
00419 
00420 AVCodec ff_xan_wc4_decoder = {
00421     .name           = "xan_wc4",
00422     .type           = AVMEDIA_TYPE_VIDEO,
00423     .id             = CODEC_ID_XAN_WC4,
00424     .priv_data_size = sizeof(XanContext),
00425     .init           = xan_decode_init,
00426     .close          = xan_decode_end,
00427     .decode         = xan_decode_frame,
00428     .capabilities   = CODEC_CAP_DR1,
00429     .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
00430 };
00431 
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