3 * Copyright (c) 2003 Michael Niedermayer
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
25 * This is very similar to intra only MPEG1.
30 #include "mpegvideo.h"
35 typedef struct MDECContext{
36 AVCodecContext *avctx;
48 DECLARE_ALIGNED_8(DCTELEM, block[6][64]);
49 DECLARE_ALIGNED_8(uint16_t, intra_matrix[64]);
50 DECLARE_ALIGNED_8(int, q_intra_matrix[64]);
51 uint8_t *bitstream_buffer;
52 unsigned int bitstream_buffer_size;
53 int block_last_index[6];
56 //very similar to mpeg1
57 static inline int mdec_decode_block_intra(MDECContext *a, DCTELEM *block, int n)
59 int level, diff, i, j, run;
61 RLTable *rl = &rl_mpeg1;
62 uint8_t * const scantable= a->scantable.permutated;
63 const uint16_t *quant_matrix= ff_mpeg1_default_intra_matrix;
64 const int qscale= a->qscale;
68 block[0]= 2*get_sbits(&a->gb, 10) + 1024;
70 component = (n <= 3 ? 0 : n - 4 + 1);
71 diff = decode_dc(&a->gb, component);
74 a->last_dc[component]+= diff;
75 block[0] = a->last_dc[component]<<3;
80 OPEN_READER(re, &a->gb);
81 /* now quantify & encode AC coefs */
83 UPDATE_CACHE(re, &a->gb);
84 GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
88 } else if(level != 0) {
91 level= (level*qscale*quant_matrix[j])>>3;
92 // level= (level-1)|1;
93 level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
94 LAST_SKIP_BITS(re, &a->gb, 1);
97 run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
98 UPDATE_CACHE(re, &a->gb);
99 level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
104 level= (level*qscale*quant_matrix[j])>>3;
108 level= (level*qscale*quant_matrix[j])>>3;
113 av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
119 CLOSE_READER(re, &a->gb);
121 a->block_last_index[n] = i;
125 static inline int decode_mb(MDECContext *a, DCTELEM block[6][64]){
127 const int block_index[6]= {5,4,0,1,2,3};
129 a->dsp.clear_blocks(block[0]);
132 if( mdec_decode_block_intra(a, block[ block_index[i] ], block_index[i]) < 0)
138 static inline void idct_put(MDECContext *a, int mb_x, int mb_y){
139 DCTELEM (*block)[64]= a->block;
140 int linesize= a->picture.linesize[0];
142 uint8_t *dest_y = a->picture.data[0] + (mb_y * 16* linesize ) + mb_x * 16;
143 uint8_t *dest_cb = a->picture.data[1] + (mb_y * 8 * a->picture.linesize[1]) + mb_x * 8;
144 uint8_t *dest_cr = a->picture.data[2] + (mb_y * 8 * a->picture.linesize[2]) + mb_x * 8;
146 a->dsp.idct_put(dest_y , linesize, block[0]);
147 a->dsp.idct_put(dest_y + 8, linesize, block[1]);
148 a->dsp.idct_put(dest_y + 8*linesize , linesize, block[2]);
149 a->dsp.idct_put(dest_y + 8*linesize + 8, linesize, block[3]);
151 if(!(a->avctx->flags&CODEC_FLAG_GRAY)){
152 a->dsp.idct_put(dest_cb, a->picture.linesize[1], block[4]);
153 a->dsp.idct_put(dest_cr, a->picture.linesize[2], block[5]);
157 static int decode_frame(AVCodecContext *avctx,
158 void *data, int *data_size,
159 uint8_t *buf, int buf_size)
161 MDECContext * const a = avctx->priv_data;
162 AVFrame *picture = data;
163 AVFrame * const p= (AVFrame*)&a->picture;
167 avctx->release_buffer(avctx, p);
170 if(avctx->get_buffer(avctx, p) < 0){
171 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
174 p->pict_type= I_TYPE;
180 a->bitstream_buffer= av_fast_realloc(a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
181 for(i=0; i<buf_size; i+=2){
182 a->bitstream_buffer[i] = buf[i+1];
183 a->bitstream_buffer[i+1]= buf[i ];
185 init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);
187 /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
188 skip_bits(&a->gb, 32);
190 a->qscale= get_bits(&a->gb, 16);
191 a->version= get_bits(&a->gb, 16);
193 // printf("qscale:%d (0x%X), version:%d (0x%X)\n", a->qscale, a->qscale, a->version, a->version);
195 for(a->mb_x=0; a->mb_x<a->mb_width; a->mb_x++){
196 for(a->mb_y=0; a->mb_y<a->mb_height; a->mb_y++){
197 if( decode_mb(a, a->block) <0)
200 idct_put(a, a->mb_x, a->mb_y);
204 // p->quality= (32 + a->inv_qscale/2)/a->inv_qscale;
205 // memset(p->qscale_table, p->quality, p->qstride*a->mb_height);
207 *picture= *(AVFrame*)&a->picture;
208 *data_size = sizeof(AVPicture);
212 return (get_bits_count(&a->gb)+31)/32*4;
215 static void mdec_common_init(AVCodecContext *avctx){
216 MDECContext * const a = avctx->priv_data;
218 dsputil_init(&a->dsp, avctx);
220 a->mb_width = (avctx->coded_width + 15) / 16;
221 a->mb_height = (avctx->coded_height + 15) / 16;
223 avctx->coded_frame= (AVFrame*)&a->picture;
227 static int decode_init(AVCodecContext *avctx){
228 MDECContext * const a = avctx->priv_data;
229 AVFrame *p= (AVFrame*)&a->picture;
231 mdec_common_init(avctx);
233 ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);
236 int index= ff_zigzag_direct[i];
237 a->intra_matrix[i]= 64*ff_mpeg1_default_intra_matrix[index] / a->inv_qscale;
240 p->qstride= a->mb_width;
241 p->qscale_table= av_mallocz( p->qstride * a->mb_height);
242 avctx->pix_fmt= PIX_FMT_YUV420P;
247 static int decode_end(AVCodecContext *avctx){
248 MDECContext * const a = avctx->priv_data;
250 av_freep(&a->bitstream_buffer);
251 av_freep(&a->picture.qscale_table);
252 a->bitstream_buffer_size=0;
257 AVCodec mdec_decoder = {