PSX MDEC decoder, based upon some code from Sebastian Jedruszkiewicz <elf at frogger dot rules dot pl>

note: completly untested, no demuxer yet

Originally committed as revision 2134 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 292 insertions, 0 deletions

diff --git a/libavcodec/mdec.c b/libavcodec/mdec.c
new file mode 100644
index 0000000000..176ee9b8f7
--- /dev/null
+++ b/libavcodec/mdec.c
@@ -0,0 +1,292 @@
+/*
+ * PSX MDEC codec
+ * Copyright (c) 2003 Michael Niedermayer
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
+ */
+ 
+/**
+ * @file mdec.c
+ * PSX MDEC codec.
+ * This is very similar to intra only MPEG1.
+ */
+ 
+#include "avcodec.h"
+#include "dsputil.h"
+#include "mpegvideo.h"
+
+//#undef NDEBUG
+//#include <assert.h>
+
+typedef struct MDECContext{
+    AVCodecContext *avctx;
+    DSPContext dsp;
+    AVFrame picture;
+    PutBitContext pb;
+    GetBitContext gb;
+    ScanTable scantable;
+    int version;
+    int qscale;
+    int last_dc[3];
+    int mb_width;
+    int mb_height;
+    int mb_x, mb_y;
+    DCTELEM __align8 block[6][64];
+    uint16_t __align8 intra_matrix[64];
+    int __align8 q_intra_matrix[64];
+    uint8_t *bitstream_buffer;
+    int bitstream_buffer_size;
+    int block_last_index[6];
+} MDECContext;
+
+//very similar to mpeg1
+static inline int mdec_decode_block_intra(MDECContext *a, DCTELEM *block, int n)
+{
+    int level, diff, i, j, run;
+    int component;
+    RLTable *rl = &rl_mpeg1;
+    uint8_t * const scantable= a->scantable.permutated;
+    const uint16_t *quant_matrix= ff_mpeg1_default_intra_matrix;
+    const int qscale= a->qscale;
+
+    /* DC coef */
+    if(a->version==2){
+        block[0]= get_sbits(&a->gb, 11);
+    }else{
+        component = (n <= 3 ? 0 : n - 4 + 1);
+        diff = decode_dc(&a->gb, component);
+        if (diff >= 0xffff)
+            return -1;
+        a->last_dc[component]+= diff;
+        block[0] = a->last_dc[component]<<3;
+    }
+    
+    i = 0;
+    {
+        OPEN_READER(re, &a->gb);    
+        /* now quantify & encode AC coefs */
+        for(;;) {
+            UPDATE_CACHE(re, &a->gb);
+            GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2);
+            
+            if(level == 127){
+                break;
+            } else if(level != 0) {
+                i += run;
+                j = scantable[i];
+                level= (level*qscale*quant_matrix[j])>>3;
+                level= (level-1)|1;
+                level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
+                LAST_SKIP_BITS(re, &a->gb, 1);
+            } else {
+                /* escape */
+                run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
+                UPDATE_CACHE(re, &a->gb);
+                level = SHOW_SBITS(re, &a->gb, 8); SKIP_BITS(re, &a->gb, 8);
+                if (level == -128) {
+                    level = SHOW_UBITS(re, &a->gb, 8) - 256; LAST_SKIP_BITS(re, &a->gb, 8);
+                } else if (level == 0) {
+                    level = SHOW_UBITS(re, &a->gb, 8)      ; LAST_SKIP_BITS(re, &a->gb, 8);
+                }
+                i += run;
+                j = scantable[i];
+/*                if(level<0){
+                    level= -level;
+                    level= (level*qscale*quant_matrix[j])>>4;
+                    level= (level-1)|1;
+                    level= -level;
+                }else{*/
+                    level= (level*qscale*quant_matrix[j])>>4;
+/*                    level= (level-1)|1;
+                }*/
+            }
+            if (i > 63){
+                fprintf(stderr, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
+                return -1;
+            }
+
+            block[j] = level;
+        }
+        CLOSE_READER(re, &a->gb);
+    }
+    a->block_last_index[n] = i;
+    return 0;
+}
+
+static inline int decode_mb(MDECContext *a, DCTELEM block[6][64]){
+    int i;
+
+    a->dsp.clear_blocks(block[0]);
+    
+    for(i=5; i>=0; i--){
+        if( mdec_decode_block_intra(a, block[i], i) < 0) 
+            return -1;
+    }
+    return 0;
+}
+
+static inline void idct_put(MDECContext *a, int mb_x, int mb_y){
+    DCTELEM (*block)[64]= a->block;
+    int linesize= a->picture.linesize[0];
+    
+    uint8_t *dest_y  = a->picture.data[0] + (mb_y * 16* linesize              ) + mb_x * 16;
+    uint8_t *dest_cb = a->picture.data[1] + (mb_y * 8 * a->picture.linesize[1]) + mb_x * 8;
+    uint8_t *dest_cr = a->picture.data[2] + (mb_y * 8 * a->picture.linesize[2]) + mb_x * 8;
+
+    a->dsp.idct_put(dest_y                 , linesize, block[0]);
+    a->dsp.idct_put(dest_y              + 8, linesize, block[1]);
+    a->dsp.idct_put(dest_y + 8*linesize    , linesize, block[2]);
+    a->dsp.idct_put(dest_y + 8*linesize + 8, linesize, block[3]);
+
+    if(!(a->avctx->flags&CODEC_FLAG_GRAY)){
+        a->dsp.idct_put(dest_cb, a->picture.linesize[1], block[4]);
+        a->dsp.idct_put(dest_cr, a->picture.linesize[2], block[5]);
+    }
+}
+
+static int decode_frame(AVCodecContext *avctx, 
+                        void *data, int *data_size,
+                        uint8_t *buf, int buf_size)
+{
+    MDECContext * const a = avctx->priv_data;
+    AVFrame *picture = data;
+    AVFrame * const p= (AVFrame*)&a->picture;
+    int i;
+
+    *data_size = 0;
+
+    /* special case for last picture */
+    if (buf_size == 0) {
+        return 0;
+    }
+
+    if(p->data[0])
+        avctx->release_buffer(avctx, p);
+
+    p->reference= 0;
+    if(avctx->get_buffer(avctx, p) < 0){
+        fprintf(stderr, "get_buffer() failed\n");
+        return -1;
+    }
+    p->pict_type= I_TYPE;
+    p->key_frame= 1;
+    a->last_dc[0]=
+    a->last_dc[1]=
+    a->last_dc[2]= 0;
+
+    a->bitstream_buffer= av_fast_realloc(a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
+    for(i=0; 2*i<buf_size; i+=2){
+        ((uint16_t*)a->bitstream_buffer)[i]  = ((uint16_t*)buf)[i+1];
+        ((uint16_t*)a->bitstream_buffer)[i+1]= ((uint16_t*)buf)[i  ];
+    }
+//    a->dsp.bswap_buf((uint32_t*)a->bitstream_buffer, (uint32_t*)buf, buf_size/4);
+    init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);
+    
+    a->qscale=  get_bits(&a->gb, 16);
+    a->version= get_bits(&a->gb, 16);
+    skip_bits(&a->gb, 8*8); 
+    
+    printf("qscale:%d, version:%d\n", a->qscale, a->version);
+    
+    for(a->mb_y=0; a->mb_y<a->mb_height; a->mb_y++){
+        for(a->mb_x=0; a->mb_x<a->mb_width; a->mb_x++){
+            if( decode_mb(a, a->block) <0)
+                return -1;
+             
+            idct_put(a, a->mb_x, a->mb_y);
+        }
+    }
+
+#if 0    
+int i;
+printf("%d %d\n", 8*buf_size, get_bits_count(&a->gb));
+for(i=get_bits_count(&a->gb); i<8*buf_size; i++){
+    printf("%d", get_bits1(&a->gb));
+}
+
+for(i=0; i<s->avctx->extradata_size; i++){
+    printf("%c\n", ((uint8_t*)s->avctx->extradata)[i]);
+}
+#endif
+
+//    p->quality= (32 + a->inv_qscale/2)/a->inv_qscale;
+//    memset(p->qscale_table, p->quality, p->qstride*a->mb_height);
+    
+    *picture= *(AVFrame*)&a->picture;
+    *data_size = sizeof(AVPicture);
+
+    emms_c();
+    
+    return (get_bits_count(&a->gb)+31)/32*4;
+}
+
+static void mdec_common_init(AVCodecContext *avctx){
+    MDECContext * const a = avctx->priv_data;
+
+    dsputil_init(&a->dsp, avctx);
+
+    a->mb_width   = (avctx->width  + 15) / 16;
+    a->mb_height  = (avctx->height + 15) / 16;
+
+    avctx->coded_frame= (AVFrame*)&a->picture;
+    a->avctx= avctx;
+}
+
+static int decode_init(AVCodecContext *avctx){
+    MDECContext * const a = avctx->priv_data;
+    AVFrame *p= (AVFrame*)&a->picture;
+    int i;
+ 
+    mdec_common_init(avctx);
+    init_vlcs();
+    ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);
+/*
+    for(i=0; i<64; i++){
+        int index= ff_zigzag_direct[i];
+        a->intra_matrix[i]= 64*ff_mpeg1_default_intra_matrix[index] / a->inv_qscale;
+    }
+*/
+    p->qstride= a->mb_width;
+    p->qscale_table= av_mallocz( p->qstride * a->mb_height);
+
+    return 0;
+}
+
+static int decode_end(AVCodecContext *avctx){
+    MDECContext * const a = avctx->priv_data;
+
+    av_freep(&a->bitstream_buffer);
+    av_freep(&a->picture.qscale_table);
+    a->bitstream_buffer_size=0;
+    
+    avcodec_default_free_buffers(avctx);
+
+    return 0;
+}
+
+AVCodec mdec_decoder = {
+    "mdec",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_MDEC,
+    sizeof(MDECContext),
+    decode_init,
+    NULL,
+    decode_end,
+    decode_frame,
+    CODEC_CAP_DR1,
+};
+