3 * Copyright (c) 2003 Michael Niedermayer
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
27 * This is very similar to intra only MPEG1.
32 #include "mpegvideo.h"
37 typedef struct MDECContext{
38 AVCodecContext *avctx;
50 DECLARE_ALIGNED_8(DCTELEM, block[6][64]);
51 DECLARE_ALIGNED_8(uint16_t, intra_matrix[64]);
52 DECLARE_ALIGNED_8(int, q_intra_matrix[64]);
53 uint8_t *bitstream_buffer;
54 unsigned int bitstream_buffer_size;
55 int block_last_index[6];
58 //very similar to mpeg1
59 static inline int mdec_decode_block_intra(MDECContext *a, DCTELEM *block, int n)
61 int level, diff, i, j, run;
63 RLTable *rl = &rl_mpeg1;
64 uint8_t * const scantable= a->scantable.permutated;
65 const uint16_t *quant_matrix= ff_mpeg1_default_intra_matrix;
66 const int qscale= a->qscale;
70 block[0]= 2*get_sbits(&a->gb, 10) + 1024;
72 component = (n <= 3 ? 0 : n - 4 + 1);
73 diff = decode_dc(&a->gb, component);
76 a->last_dc[component]+= diff;
77 block[0] = a->last_dc[component]<<3;
82 OPEN_READER(re, &a->gb);
83 /* now quantify & encode AC coefs */
85 UPDATE_CACHE(re, &a->gb);
86 GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
90 } else if(level != 0) {
93 level= (level*qscale*quant_matrix[j])>>3;
94 // level= (level-1)|1;
95 level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
96 LAST_SKIP_BITS(re, &a->gb, 1);
99 run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
100 UPDATE_CACHE(re, &a->gb);
101 level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
106 level= (level*qscale*quant_matrix[j])>>3;
110 level= (level*qscale*quant_matrix[j])>>3;
115 av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
121 CLOSE_READER(re, &a->gb);
123 a->block_last_index[n] = i;
127 static inline int decode_mb(MDECContext *a, DCTELEM block[6][64]){
129 const int block_index[6]= {5,4,0,1,2,3};
131 a->dsp.clear_blocks(block[0]);
134 if( mdec_decode_block_intra(a, block[ block_index[i] ], block_index[i]) < 0)
140 static inline void idct_put(MDECContext *a, int mb_x, int mb_y){
141 DCTELEM (*block)[64]= a->block;
142 int linesize= a->picture.linesize[0];
144 uint8_t *dest_y = a->picture.data[0] + (mb_y * 16* linesize ) + mb_x * 16;
145 uint8_t *dest_cb = a->picture.data[1] + (mb_y * 8 * a->picture.linesize[1]) + mb_x * 8;
146 uint8_t *dest_cr = a->picture.data[2] + (mb_y * 8 * a->picture.linesize[2]) + mb_x * 8;
148 a->dsp.idct_put(dest_y , linesize, block[0]);
149 a->dsp.idct_put(dest_y + 8, linesize, block[1]);
150 a->dsp.idct_put(dest_y + 8*linesize , linesize, block[2]);
151 a->dsp.idct_put(dest_y + 8*linesize + 8, linesize, block[3]);
153 if(!(a->avctx->flags&CODEC_FLAG_GRAY)){
154 a->dsp.idct_put(dest_cb, a->picture.linesize[1], block[4]);
155 a->dsp.idct_put(dest_cr, a->picture.linesize[2], block[5]);
159 static int decode_frame(AVCodecContext *avctx,
160 void *data, int *data_size,
161 uint8_t *buf, int buf_size)
163 MDECContext * const a = avctx->priv_data;
164 AVFrame *picture = data;
165 AVFrame * const p= (AVFrame*)&a->picture;
169 avctx->release_buffer(avctx, p);
172 if(avctx->get_buffer(avctx, p) < 0){
173 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
176 p->pict_type= I_TYPE;
182 a->bitstream_buffer= av_fast_realloc(a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
183 for(i=0; i<buf_size; i+=2){
184 a->bitstream_buffer[i] = buf[i+1];
185 a->bitstream_buffer[i+1]= buf[i ];
187 init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);
189 /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
190 skip_bits(&a->gb, 32);
192 a->qscale= get_bits(&a->gb, 16);
193 a->version= get_bits(&a->gb, 16);
195 // printf("qscale:%d (0x%X), version:%d (0x%X)\n", a->qscale, a->qscale, a->version, a->version);
197 for(a->mb_x=0; a->mb_x<a->mb_width; a->mb_x++){
198 for(a->mb_y=0; a->mb_y<a->mb_height; a->mb_y++){
199 if( decode_mb(a, a->block) <0)
202 idct_put(a, a->mb_x, a->mb_y);
206 // p->quality= (32 + a->inv_qscale/2)/a->inv_qscale;
207 // memset(p->qscale_table, p->quality, p->qstride*a->mb_height);
209 *picture= *(AVFrame*)&a->picture;
210 *data_size = sizeof(AVPicture);
214 return (get_bits_count(&a->gb)+31)/32*4;
217 static void mdec_common_init(AVCodecContext *avctx){
218 MDECContext * const a = avctx->priv_data;
220 dsputil_init(&a->dsp, avctx);
222 a->mb_width = (avctx->coded_width + 15) / 16;
223 a->mb_height = (avctx->coded_height + 15) / 16;
225 avctx->coded_frame= (AVFrame*)&a->picture;
229 static int decode_init(AVCodecContext *avctx){
230 MDECContext * const a = avctx->priv_data;
231 AVFrame *p= (AVFrame*)&a->picture;
233 mdec_common_init(avctx);
235 ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);
238 int index= ff_zigzag_direct[i];
239 a->intra_matrix[i]= 64*ff_mpeg1_default_intra_matrix[index] / a->inv_qscale;
242 p->qstride= a->mb_width;
243 p->qscale_table= av_mallocz( p->qstride * a->mb_height);
244 avctx->pix_fmt= PIX_FMT_YUV420P;
249 static int decode_end(AVCodecContext *avctx){
250 MDECContext * const a = avctx->priv_data;
252 av_freep(&a->bitstream_buffer);
253 av_freep(&a->picture.qscale_table);
254 a->bitstream_buffer_size=0;
259 AVCodec mdec_decoder = {