nengel@2: /*
nengel@2:  * H.26L/H.264/AVC/JVT/14496-10/... parser
nengel@2:  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
nengel@2:  *
nengel@2:  * This file is part of FFmpeg.
nengel@2:  *
nengel@2:  * FFmpeg is free software; you can redistribute it and/or
nengel@2:  * modify it under the terms of the GNU Lesser General Public
nengel@2:  * License as published by the Free Software Foundation; either
nengel@2:  * version 2.1 of the License, or (at your option) any later version.
nengel@2:  *
nengel@2:  * FFmpeg is distributed in the hope that it will be useful,
nengel@2:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
nengel@2:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
nengel@2:  * Lesser General Public License for more details.
nengel@2:  *
nengel@2:  * You should have received a copy of the GNU Lesser General Public
nengel@2:  * License along with FFmpeg; if not, write to the Free Software
nengel@2:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
nengel@2:  */
nengel@2: 
nengel@2: /**
nengel@2:  * @file
nengel@2:  * H.264 / AVC / MPEG4 part10 parser.
nengel@2:  * @author Michael Niedermayer <michaelni@gmx.at>
nengel@2:  */
nengel@2: 
nengel@2: #include <unistd.h>
nengel@2: 
nengel@2: #include "golomb.h"
nengel@2: #include "libavutil/error.h"
nengel@2: #include "h264_types.h"
nengel@2: 
nengel@2: #undef NDEBUG
nengel@2: #include <assert.h>
nengel@2: 
nengel@2: #define END_NOT_FOUND (-100)
nengel@2: 
nengel@2: static int ff_h264_find_frame_end(ParserContext *s, const uint8_t *buf, int buf_size)
nengel@2: {
nengel@2:     int i;
nengel@2:     uint32_t state;
nengel@2: 
nengel@2:     state= s->state;
nengel@2:     if(state>13)
nengel@2:         state= 7;
nengel@2: 
nengel@2:     for(i=0; i<buf_size; i++){
nengel@2:         if(state==7){
nengel@2:         /* we check i<buf_size instead of i+3/7 because its simpler
nengel@2:          * and there should be FF_INPUT_BUFFER_PADDING_SIZE bytes at the end
nengel@2:          */
nengel@2:             while(i<buf_size && !((~*(const uint64_t*)(buf+i) & (*(const uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL))
nengel@2:                 i+=8;
nengel@2: 
nengel@2:             for(; i<buf_size; i++){
nengel@2:                 if(!buf[i]){
nengel@2:                     state=2;
nengel@2:                     break;
nengel@2:                 }
nengel@2:             }
nengel@2:         }else if(state<=2){
nengel@2:             if(buf[i]==1)   state^= 5; //2->7, 1->4, 0->5
nengel@2:             else if(buf[i]) state = 7;
nengel@2:             else            state>>=1; //2->1, 1->0, 0->0
nengel@2:         }else if(state<=5){
nengel@2:             int v= buf[i] & 0x1F;
nengel@2:             if(v==6 || v==7 || v==8 || v==9){
nengel@2:                 if(s->frame_start_found){
nengel@2:                     i++;
nengel@2:                     goto found;
nengel@2:                 }
nengel@2:             }else if(v==1 || v==2 || v==5){
nengel@2:                 if(s->frame_start_found){
nengel@2:                     state+=8;
nengel@2:                     continue;
nengel@2:                 }else
nengel@2:                     s->frame_start_found = 1;
nengel@2:             }
nengel@2:             state= 7;
nengel@2:         }else{
nengel@2:             if(buf[i] & 0x80)
nengel@2:                 goto found;
nengel@2:             state= 7;
nengel@2:         }
nengel@2:     }
nengel@2:     s->state= state;
nengel@2:     return END_NOT_FOUND;
nengel@2: 
nengel@2: found:
nengel@2:     s->state=7;
nengel@2:     s->frame_start_found= 0;
nengel@2:     return i-(state&5);
nengel@2: }
nengel@2: 
nengel@2: static int ff_combine_frame(ParserContext *s, GetBitContext *gb, int next, uint8_t **buf, int *buf_size)
nengel@2: {
nengel@2:     int i;
nengel@2:     /* Copy overread bytes from last frame into buffer. */
nengel@2:     for(i =0; s->overread_cnt>0; s->overread_cnt--, i++){
nengel@2:         gb->raw[s->index++]= s->overread[i];
nengel@2:     }
nengel@2: 
nengel@2:     /* EOF - END_NOT_FOUND means no next frame start is found in current partial read. If buf_size of the partial read is 0 we are at EOF */
nengel@2:     if(!*buf_size && next == END_NOT_FOUND){
nengel@2:         next= 0;
nengel@2:     }
nengel@2:     s->last_index= s->index;
nengel@2: 
nengel@2:     /* copy into buffer end return */
nengel@2:     if(next == END_NOT_FOUND){
nengel@2:         gb->raw = av_fast_realloc(gb->raw, &gb->alloc_size, (*buf_size) + s->index + FF_INPUT_BUFFER_PADDING_SIZE);
nengel@2:         memcpy(&gb->raw[s->index], *buf, *buf_size);
nengel@2:         s->index += *buf_size;
nengel@2:         return -1;
nengel@2:     }
nengel@2: 
nengel@2:     ///end found
nengel@2:     *buf_size=  s->index + next;
nengel@2:     /* append to buffer */
nengel@2: 
nengel@2:     gb->raw = av_fast_realloc(gb->raw, &gb->alloc_size, next + s->index + FF_INPUT_BUFFER_PADDING_SIZE);
nengel@2:     memcpy(&gb->raw[s->index], *buf, next + FF_INPUT_BUFFER_PADDING_SIZE );
nengel@2:     s->index = 0;
nengel@2: 
nengel@2:     /* store overread bytes */
nengel@2:     for(i=0; next < 0; next++, i++){
nengel@2:         s->state = (s->state<<8) | gb->raw[s->last_index + next];
nengel@2:         s->overread[i] = gb->raw[s->last_index + next];
nengel@2:         s->overread_cnt++;
nengel@2:     }
nengel@2: 
nengel@2:     return 0;
nengel@2: }
nengel@2: 
nengel@2: static int h264_parse(ParserContext *s, GetBitContext *gb,
nengel@2:                       uint8_t *buf, int buf_size)
nengel@2: {
nengel@2:     int next;
nengel@2: 
nengel@2:     next= ff_h264_find_frame_end(s, buf, buf_size);
nengel@2: 
nengel@2:     if (ff_combine_frame(s, gb, next, &buf, &buf_size) < 0) {
nengel@2:         gb->buf_size = 0;
nengel@2:         return buf_size;
nengel@2:     }
nengel@2: 
nengel@2:     if(next<0 && next != END_NOT_FOUND){
nengel@2:         assert(s->last_index + next >= 0 );
nengel@2:         ff_h264_find_frame_end(s, &gb->raw[s->last_index + next], -next); //update state
nengel@2:     }
nengel@2: 
nengel@2:     gb->buf_size = buf_size;
nengel@2:     return next;
nengel@2: }
nengel@2: 
nengel@2: static int ff_raw_read_partial_packet(ParserContext *pc)
nengel@2: {
nengel@2:     int len= -1;
nengel@2: 
nengel@2:     if (!pc->eof_reached){
nengel@2:         len = read( pc->ifile, pc->data, pc->buffer_size);
nengel@2: //         printf("read task %d\t%d\n", pc->ifile, len); fflush(NULL);
nengel@2:         if (len < pc->buffer_size) {
nengel@2:             pc->eof_reached = 1;
nengel@2:         }
nengel@2:     }
nengel@2: 
nengel@2:     return len;
nengel@2: }
nengel@2: 
nengel@2: void av_read_frame_internal(ParserContext *pc, GetBitContext *gb){
nengel@2:     int len;
nengel@2:     uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE]={0};
nengel@2:     av_fast_malloc(&gb->raw, &gb->alloc_size, 2048+FF_INPUT_BUFFER_PADDING_SIZE);
nengel@2: 
nengel@2:     //Parsing is performed before read, since there are ussually leftovers from parsing the previous frame.
nengel@2:     for(;;) {
nengel@2:         if (pc->cur_len>0){
nengel@2:             len = h264_parse(pc, gb, pc->cur_ptr, pc->cur_len);
nengel@2:             if (len<0)
nengel@2:                 len =0;
nengel@2:             //* increment read pointer */
nengel@2:             pc->cur_ptr += len;
nengel@2:             pc->cur_len -= len;
nengel@2: 
nengel@2:             if (gb->buf_size) {
nengel@2:                 break;
nengel@2:             }
nengel@2:         }
nengel@2: 
nengel@2:         //check for ret and not parser->eof_reached as one "read" can contain more than 1 frame
nengel@2:         pc->size= ff_raw_read_partial_packet(pc);
nengel@2:         if (pc->size < 0) {
nengel@2:             pc->final_frame =1;
nengel@2:             /* return the last frames, if any */
nengel@2:             h264_parse(pc, gb, dummy_buf, 0);
nengel@2:             break;
nengel@2:         }
nengel@2:         pc->cur_ptr = pc->data;
nengel@2:         pc->cur_len = pc->size;
nengel@2:     }
nengel@2: 
nengel@2:     assert(gb->raw!=NULL);
nengel@2: 
nengel@2: }
nengel@2: 
nengel@2: ParserContext *get_parse_context(int ifile){
nengel@2:     ParserContext *pc = av_mallocz(sizeof(ParserContext));
nengel@2:     pc->buffer_size = 2048;
nengel@2:     pc->final_frame = 0;
nengel@2:     pc->cur_len= 0;
nengel@2:     pc->data = av_mallocz(2048 + FF_INPUT_BUFFER_PADDING_SIZE);
nengel@2:     pc->size = 2048;
nengel@2:     pc->eof_reached =0;
nengel@2:     pc->ifile = ifile;
nengel@2: 
nengel@2:     return pc;
nengel@2: }
nengel@2: 
nengel@2: void free_parse_context(ParserContext *pc){
nengel@2:     av_free(pc->data);
nengel@2:     av_free(pc);
nengel@2: }