#include "../mpeg3private.h" #include "../mpeg3protos.h" #include "mpeg3video.h" #include #include unsigned int mpeg3bits_next_startcode(mpeg3_bits_t* stream) { /* Perform forwards search */ mpeg3bits_byte_align(stream); /* Perform search */ while((mpeg3bits_showbits32_noptr(stream) >> 8) != MPEG3_PACKET_START_CODE_PREFIX && !mpeg3bits_eof(stream)) { mpeg3bits_getbyte_noptr(stream); } return mpeg3bits_showbits32_noptr(stream); } /* Line up on the beginning of the next code. */ int mpeg3video_next_code(mpeg3_bits_t* stream, unsigned int code) { while(!mpeg3bits_eof(stream) && mpeg3bits_showbits32_noptr(stream) != code) { mpeg3bits_getbyte_noptr(stream); } return mpeg3bits_eof(stream); } /* Line up on the beginning of the previous code. */ int mpeg3video_prev_code(mpeg3_bits_t* stream, unsigned int code) { while(!mpeg3bits_bof(stream) && mpeg3bits_showbits_reverse(stream, 32) != code) { mpeg3bits_getbits_reverse(stream, 8); } return mpeg3bits_bof(stream); } long mpeg3video_goptimecode_to_frame(mpeg3video_t *video) { /* printf("mpeg3video_goptimecode_to_frame %d %d %d %d %f\n", */ /* video->gop_timecode.hour, video->gop_timecode.minute, video->gop_timecode.second, video->gop_timecode.frame, video->frame_rate); */ return (long)(video->gop_timecode.hour * 3600 * video->frame_rate + video->gop_timecode.minute * 60 * video->frame_rate + video->gop_timecode.second * video->frame_rate + video->gop_timecode.frame) - 1 - video->first_frame; } int mpeg3video_match_refframes(mpeg3video_t *video) { unsigned char *dst, *src; int i, j, size; for(i = 0; i < 3; i++) { if(video->newframe[i]) { if(video->newframe[i] == video->refframe[i]) { src = video->refframe[i]; dst = video->oldrefframe[i]; } else { src = video->oldrefframe[i]; dst = video->refframe[i]; } if(i == 0) size = video->coded_picture_width * video->coded_picture_height + 32 * video->coded_picture_width; else size = video->chrom_width * video->chrom_height + 32 * video->chrom_width; memcpy(dst, src, size); } } return 0; } int mpeg3video_seek(mpeg3video_t *video) { long this_gop_start; int result = 0; int back_step; int attempts; mpeg3_t *file = video->file; mpeg3_bits_t *vstream = video->vstream; double percentage; long frame_number; int match_refframes = 1; /* Seek to a percentage */ if(video->percentage_seek >= 0) { percentage = video->percentage_seek; video->percentage_seek = -1; mpeg3bits_seek_percentage(vstream, percentage); // Go to previous I-frame mpeg3bits_start_reverse(vstream); result = mpeg3video_prev_code(vstream, MPEG3_GOP_START_CODE); if(!result) mpeg3bits_getbits_reverse(vstream, 32); mpeg3bits_start_forward(vstream); if(mpeg3bits_tell_percentage(vstream) < 0) mpeg3bits_seek_percentage(vstream, 0); // Read up to the correct percentage result = 0; while(!result && mpeg3bits_tell_percentage(vstream) < percentage) { result = mpeg3video_read_frame_backend(video, 0); if(match_refframes) mpeg3video_match_refframes(video); match_refframes = 0; } } else /* Seek to a frame */ if(video->frame_seek >= 0) { frame_number = video->frame_seek; video->frame_seek = -1; if(frame_number < 0) frame_number = 0; if(frame_number > video->maxframe) frame_number = video->maxframe; /* Seek to start of file */ if(frame_number < 16) { video->repeat_count = video->current_repeat = 0; mpeg3bits_seek_start(vstream); video->framenum = 0; result = mpeg3video_drop_frames(video, frame_number - video->framenum); } else { /* Seek to an I frame. */ if((frame_number < video->framenum || frame_number - video->framenum > MPEG3_SEEK_THRESHOLD)) { /* Elementary stream */ if(file->is_video_stream) { mpeg3_t *file = video->file; mpeg3_vtrack_t *track = video->track; long byte = (long)((float)(mpeg3demuxer_total_bytes(vstream->demuxer) / track->total_frames) * frame_number); long minimum = 65535; int done = 0; //printf("seek elementary %d\n", frame_number); /* Get GOP just before frame */ do { result = mpeg3bits_seek_byte(vstream, byte); mpeg3bits_start_reverse(vstream); if(!result) result = mpeg3video_prev_code(vstream, MPEG3_GOP_START_CODE); mpeg3bits_start_forward(vstream); mpeg3bits_getbits(vstream, 8); if(!result) result = mpeg3video_getgophdr(video); this_gop_start = mpeg3video_goptimecode_to_frame(video); //printf("wanted %ld guessed %ld byte %ld result %d\n", frame_number, this_gop_start, byte, result); if(labs(this_gop_start - frame_number) >= labs(minimum)) done = 1; else { minimum = this_gop_start - frame_number; byte += (long)((float)(frame_number - this_gop_start) * (float)(mpeg3demuxer_total_bytes(vstream->demuxer) / track->total_frames)); if(byte < 0) byte = 0; } }while(!result && !done); //printf("wanted %d guessed %d\n", frame_number, this_gop_start); if(!result) { video->framenum = this_gop_start; result = mpeg3video_drop_frames(video, frame_number - video->framenum); } } else /* System stream */ { mpeg3bits_seek_time(vstream, (double)frame_number / video->frame_rate); percentage = mpeg3bits_tell_percentage(vstream); //printf("seek frame %ld percentage %f byte %ld\n", frame_number, percentage, mpeg3bits_tell(vstream)); mpeg3bits_start_reverse(vstream); mpeg3video_prev_code(vstream, MPEG3_GOP_START_CODE); mpeg3bits_getbits_reverse(vstream, 32); mpeg3bits_start_forward(vstream); //printf("seek system 1 %f\n", (double)frame_number / video->frame_rate); while(!result && mpeg3bits_tell_percentage(vstream) < percentage) { result = mpeg3video_read_frame_backend(video, 0); if(match_refframes) mpeg3video_match_refframes(video); //printf("seek system 2 %f %f\n", mpeg3bits_tell_percentage(vstream) / percentage); match_refframes = 0; } //printf("seek system 3 %f\n", (double)frame_number / video->frame_rate); } video->framenum = frame_number; } else // Drop frames { mpeg3video_drop_frames(video, frame_number - video->framenum); } } } return result; } int mpeg3video_drop_frames(mpeg3video_t *video, long frames) { int result = 0; long frame_number = video->framenum + frames; /* Read the selected number of frames and skip b-frames */ while(!result && frame_number > video->framenum) { result = mpeg3video_read_frame_backend(video, frame_number - video->framenum); } return result; }