• Main Page
  • Related Pages
  • Modules
  • Data Structures
  • Files
  • File List
  • Globals

libavcodec/eatgq.c

Go to the documentation of this file.
00001 /*
00002  * Electronic Arts TGQ Video Decoder
00003  * Copyright (c) 2007-2008 Peter Ross <pross@xvid.org>
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 St, Fifth Floor, Boston, MA  02110-1301  USA
00020  */
00021 
00031 #include "avcodec.h"
00032 #define ALT_BITSTREAM_READER_LE
00033 #include "bitstream.h"
00034 #include "bytestream.h"
00035 #include "dsputil.h"
00036 #include "aandcttab.h"
00037 
00038 typedef struct TgqContext {
00039     AVCodecContext *avctx;
00040     DSPContext dsp;
00041     AVFrame frame;
00042     int width,height;
00043     ScanTable scantable;
00044     int qtable[64];
00045 } TgqContext;
00046 
00047 static av_cold int tgq_decode_init(AVCodecContext *avctx){
00048     TgqContext *s = avctx->priv_data;
00049     s->avctx = avctx;
00050     if(avctx->idct_algo==FF_IDCT_AUTO)
00051         avctx->idct_algo=FF_IDCT_EA;
00052     dsputil_init(&s->dsp, avctx);
00053     ff_init_scantable(s->dsp.idct_permutation, &s->scantable, ff_zigzag_direct);
00054     avctx->time_base = (AVRational){1, 15};
00055     avctx->pix_fmt = PIX_FMT_YUV420P;
00056     return 0;
00057 }
00058 
00059 static void tgq_decode_block(TgqContext *s, DCTELEM block[64], GetBitContext *gb){
00060     uint8_t *perm = s->scantable.permutated;
00061     int i,j,value;
00062     block[0] = get_sbits(gb,8) * s->qtable[0];
00063     for(i=1; i<64; ) {
00064         switch(show_bits(gb,3)) {
00065         case 4:
00066             block[perm[i++]] = 0;
00067         case 0:
00068             block[perm[i++]] = 0;
00069             skip_bits(gb,3);
00070             break;
00071         case 5:
00072         case 1:
00073             skip_bits(gb,2);
00074             value = get_bits(gb,6);
00075             for(j=0; j<value; j++)
00076                 block[perm[i++]] = 0;
00077             break;
00078         case 6:
00079             skip_bits(gb,3);
00080             block[perm[i]] = -s->qtable[perm[i]];
00081             i++;
00082             break;
00083         case 2:
00084             skip_bits(gb,3);
00085             block[perm[i]] = s->qtable[perm[i]];
00086             i++;
00087             break;
00088         case 7: // 111b
00089         case 3: // 011b
00090             skip_bits(gb,2);
00091             if (show_bits(gb,6)==0x3F) {
00092                 skip_bits(gb, 6);
00093                 block[perm[i]] = get_sbits(gb,8)*s->qtable[perm[i]];
00094             }else{
00095                 block[perm[i]] = get_sbits(gb,6)*s->qtable[perm[i]];
00096             }
00097             i++;
00098             break;
00099         }
00100     }
00101     block[0] += 128<<4;
00102 }
00103 
00104 static void tgq_idct_put_mb(TgqContext *s, DCTELEM (*block)[64], int mb_x, int mb_y){
00105     int linesize= s->frame.linesize[0];
00106     uint8_t *dest_y  = s->frame.data[0] + (mb_y * 16* linesize            ) + mb_x * 16;
00107     uint8_t *dest_cb = s->frame.data[1] + (mb_y * 8 * s->frame.linesize[1]) + mb_x * 8;
00108     uint8_t *dest_cr = s->frame.data[2] + (mb_y * 8 * s->frame.linesize[2]) + mb_x * 8;
00109 
00110     s->dsp.idct_put(dest_y                 , linesize, block[0]);
00111     s->dsp.idct_put(dest_y              + 8, linesize, block[1]);
00112     s->dsp.idct_put(dest_y + 8*linesize    , linesize, block[2]);
00113     s->dsp.idct_put(dest_y + 8*linesize + 8, linesize, block[3]);
00114     if(!(s->avctx->flags&CODEC_FLAG_GRAY)){
00115          s->dsp.idct_put(dest_cb, s->frame.linesize[1], block[4]);
00116          s->dsp.idct_put(dest_cr, s->frame.linesize[2], block[5]);
00117     }
00118 }
00119 
00120 static inline void tgq_dconly(TgqContext *s, unsigned char *dst, int dst_stride, int dc){
00121     int level = av_clip_uint8((dc*s->qtable[0] + 2056)>>4);
00122     int j;
00123     for(j=0;j<8;j++)
00124         memset(dst+j*dst_stride, level, 8);
00125 }
00126 
00127 static void tgq_idct_put_mb_dconly(TgqContext *s, int mb_x, int mb_y, const int8_t *dc)
00128 {
00129     int linesize= s->frame.linesize[0];
00130     uint8_t *dest_y  = s->frame.data[0] + (mb_y * 16* linesize            ) + mb_x * 16;
00131     uint8_t *dest_cb = s->frame.data[1] + (mb_y * 8 * s->frame.linesize[1]) + mb_x * 8;
00132     uint8_t *dest_cr = s->frame.data[2] + (mb_y * 8 * s->frame.linesize[2]) + mb_x * 8;
00133     tgq_dconly(s,dest_y                 , linesize, dc[0]);
00134     tgq_dconly(s,dest_y              + 8, linesize, dc[1]);
00135     tgq_dconly(s,dest_y + 8*linesize    , linesize, dc[2]);
00136     tgq_dconly(s,dest_y + 8*linesize + 8, linesize, dc[3]);
00137     if(!(s->avctx->flags&CODEC_FLAG_GRAY)) {
00138         tgq_dconly(s,dest_cb, s->frame.linesize[1], dc[4]);
00139         tgq_dconly(s,dest_cr, s->frame.linesize[2], dc[5]);
00140     }
00141 }
00142 
00143 static void tgq_decode_mb(TgqContext *s, int mb_y, int mb_x, const int8_t **bs, const int8_t *buf_end){
00144     int mode;
00145     int i;
00146     int8_t dc[6];
00147     DCTELEM block[6][64];
00148 
00149     mode = bytestream_get_byte((const uint8_t**)bs);
00150     if (mode>buf_end-*bs) {
00151         av_log(s->avctx, AV_LOG_ERROR, "truncated macroblock\n");
00152         return;
00153     }
00154 
00155     if (mode>12) {
00156         GetBitContext gb;
00157         init_get_bits(&gb, *bs, mode*8);
00158         for(i=0; i<6; i++)
00159             tgq_decode_block(s, block[i], &gb);
00160         tgq_idct_put_mb(s, block, mb_x, mb_y);
00161     }else{
00162         if (mode==3) {
00163             memset(dc, (*bs)[0], 4);
00164             dc[4] = (*bs)[1];
00165             dc[5] = (*bs)[2];
00166         }else if (mode==6) {
00167             memcpy(dc, *bs, 6);
00168         }else if (mode==12) {
00169             for(i=0; i<6; i++)
00170                 dc[i] = (*bs)[i*2];
00171         }else{
00172             av_log(s->avctx, AV_LOG_ERROR, "unsupported mb mode %i\n", mode);
00173         }
00174         tgq_idct_put_mb_dconly(s, mb_x, mb_y, dc);
00175     }
00176     *bs += mode;
00177 }
00178 
00179 static void tgq_calculate_qtable(TgqContext *s, int quant){
00180     int i,j;
00181     const int a = (14*(100-quant))/100 + 1;
00182     const int b = (11*(100-quant))/100 + 4;
00183     for(j=0;j<8;j++)
00184     for(i=0;i<8;i++)
00185         if (s->avctx->idct_algo==FF_IDCT_EA)
00186             s->qtable[j*8+i] = ((a*(j+i)/(7+7) + b)*ff_inv_aanscales[j*8+i])>>(14-4);
00187         else
00188             s->qtable[j*8+i] = (a*(j+i)/(7+7) + b)<<3;
00189 }
00190 
00191 static int tgq_decode_frame(AVCodecContext *avctx,
00192                             void *data, int *data_size,
00193                             const uint8_t *buf, int buf_size){
00194     const uint8_t *buf_start = buf;
00195     const uint8_t *buf_end = buf + buf_size;
00196     TgqContext *s = avctx->priv_data;
00197     int x,y;
00198 
00199     int big_endian = AV_RL32(&buf[4]) > 0x000FFFFF;
00200     buf += 8;
00201 
00202     if(8>buf_end-buf) {
00203         av_log(avctx, AV_LOG_WARNING, "truncated header\n");
00204         return -1;
00205     }
00206     s->width  = big_endian ? AV_RB16(&buf[0]) : AV_RL16(&buf[0]);
00207     s->height = big_endian ? AV_RB16(&buf[2]) : AV_RL16(&buf[2]);
00208 
00209     if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
00210         avcodec_set_dimensions(s->avctx, s->width, s->height);
00211         if (s->frame.data[0])
00212             avctx->release_buffer(avctx, &s->frame);
00213     }
00214     tgq_calculate_qtable(s, buf[4]);
00215     buf += 8;
00216 
00217     if (!s->frame.data[0]) {
00218         s->frame.key_frame = 1;
00219         s->frame.pict_type = FF_I_TYPE;
00220         s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
00221         if (avctx->get_buffer(avctx, &s->frame)) {
00222             av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00223             return -1;
00224         }
00225     }
00226 
00227     for (y=0; y<(avctx->height+15)/16; y++)
00228     for (x=0; x<(avctx->width+15)/16; x++)
00229         tgq_decode_mb(s, y, x, (const int8_t**)&buf, (const int8_t*)buf_end);
00230 
00231     *data_size = sizeof(AVFrame);
00232     *(AVFrame*)data = s->frame;
00233 
00234     return buf-buf_start;
00235 }
00236 
00237 static av_cold int tgq_decode_end(AVCodecContext *avctx){
00238     TgqContext *s = avctx->priv_data;
00239     if (s->frame.data[0])
00240         s->avctx->release_buffer(avctx, &s->frame);
00241     return 0;
00242 }
00243 
00244 AVCodec eatgq_decoder = {
00245     "eatgq",
00246     CODEC_TYPE_VIDEO,
00247     CODEC_ID_TGQ,
00248     sizeof(TgqContext),
00249     tgq_decode_init,
00250     NULL,
00251     tgq_decode_end,
00252     tgq_decode_frame,
00253     CODEC_CAP_DR1,
00254     .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts TGQ video"),
00255 };

Generated on Tue Nov 4 2014 12:59:21 for ffmpeg by  doxygen 1.7.1