Author: ods15 Date: Fri Jan 26 17:28:56 2007 New Revision: 275 Modified: trunk/libnut/demuxer.c trunk/libnut/priv.h Log: improovements to binary search to prevent searching the same damaged area twice seek backwards to look for syncpoint before damaged data and mark the area between as scanned Modified: trunk/libnut/demuxer.c ============================================================================== --- trunk/libnut/demuxer.c (original) +++ trunk/libnut/demuxer.c Fri Jan 26 17:28:56 2007 @@ -1143,13 +1143,13 @@ return 0; } -static off_t seek_interpolate(int max_distance, double time_pos, off_t lo, off_t hi, double lo_pd, double hi_pd) { +static off_t seek_interpolate(int max_distance, double time_pos, off_t lo, off_t hi, double lo_pd, double hi_pd, off_t fake_hi) { double weight = 19./20.; off_t guess; - if (hi - lo < max_distance) guess = lo + 16; + if (fake_hi - lo < max_distance) guess = lo + 16; else { // linear interpolation guess = (lo + (double)(hi-lo)/(hi_pd-lo_pd) * (time_pos-lo_pd))*weight + (lo+hi)/2.*(1.-weight); - if (hi - guess < max_distance) guess = hi - max_distance; //(lo + hi)/2; + if (fake_hi - guess < max_distance) guess = fake_hi - max_distance; //(lo + hi)/2; } if (guess < lo + 16) guess = lo + 16; return guess; @@ -1158,7 +1158,7 @@ static int binary_search_syncpoint(nut_context_t * nut, double time_pos, off_t * start, off_t * end, syncpoint_t * stopper) { int i, err = 0; syncpoint_t s; - off_t fake_hi; + off_t fake_hi, * guess = &nut->binary_guess; uint64_t timebases[nut->timebase_count]; syncpoint_list_t * sl = &nut->syncpoints; int a = 0; @@ -1200,34 +1200,53 @@ #define LO (sl->s[i]) #define HI (sl->s[i+1]) - fake_hi = nut->seek_status ? nut->seek_status : HI.pos; + fake_hi = nut->seek_status ? (nut->seek_status >> 1) : HI.pos; while (!LO.seen_next) { // start binary search between LO (sl->s[i].pos) to HI (sl->s[i+1].pos) ... - off_t guess = seek_interpolate(nut->max_distance*2, time_pos, LO.pos, fake_hi, TO_DOUBLE_PTS(LO.pts), TO_DOUBLE_PTS(HI.pts)); + if (!*guess) *guess = seek_interpolate(nut->max_distance*2, time_pos, LO.pos, HI.pos, TO_DOUBLE_PTS(LO.pts), TO_DOUBLE_PTS(HI.pts), fake_hi); - fprintf(stderr, "\n%d [ (%d,%.3f) .. (%d,%.3f) .. (%d,%.3f) ] ", i, (int)LO.pos, TO_DOUBLE_PTS(LO.pts), (int)guess, time_pos, - (int)fake_hi, TO_DOUBLE_PTS(HI.pts)); + fprintf(stderr, "\n%d [ (%d,%.3f) .. (%d,%.3f) .. (%d(%d),%.3f) ] ", i, (int)LO.pos, TO_DOUBLE_PTS(LO.pts), (int)*guess, time_pos, + (int)HI.pos, (int)fake_hi, TO_DOUBLE_PTS(HI.pts)); a++; - if (!nut->seek_status) seek_buf(nut->i, guess, SEEK_SET); - nut->seek_status = fake_hi; // so we know where to continue off... - CHECK(smart_find_syncpoint(nut, &s, 0, fake_hi)); - nut->seek_status = 0; + if (!(nut->seek_status & 1)) { + if (!nut->seek_status) seek_buf(nut->i, *guess, SEEK_SET); + nut->seek_status = fake_hi << 1; + CHECK(find_syncpoint(nut, &s, 0, fake_hi)); + nut->seek_status = 0; + } - if (s.seen_next == 1 || s.pos >= fake_hi) { // we got back to 'HI' - // either we scanned everything from LO to HI, or we keep trying - if (guess <= LO.pos + 16) LO.seen_next = 1; // we are done! - else fake_hi = guess; - continue; +scan_backwards: + if (nut->seek_status & 1 || s.seen_next == 1 || s.pos >= fake_hi) { // we got back to 'HI' + if (*guess == LO.pos + 16) { // we are done! + LO.seen_next = 1; + break; + } + // Now let's scan backwards from 'guess' to 'LO' - after this, we can set s.seen_next + if (!nut->seek_status) seek_buf(nut->i, *guess - nut->max_distance + 7, SEEK_SET); + nut->seek_status = (fake_hi << 1) + 1; + CHECK(find_syncpoint(nut, &s, 1, 0)); + nut->seek_status = 0; + s.seen_next = 1; // now this can cause LO.seen_next to be set after add_syncpoint(), it's magic } CHECK(add_syncpoint(nut, s, NULL, NULL, timebases[s.pts%nut->timebase_count] < s.pts/nut->timebase_count ? NULL : &i)); - if (HI.pos < fake_hi) fake_hi = HI.pos; + + if (s.pos - *guess > nut->max_distance * 100) { + // we just scanned a very large area of (probably) damaged data + // let's avoid scanning it again by caching the syncpoint right before it with seen_next + s.seen_next = 1; + goto scan_backwards; + } + + if (HI.pos < fake_hi) fake_hi = MIN(HI.pos, *guess); + *guess = 0; } + *guess = 0; fprintf(stderr, "\n[ (%d,%d) .. %d .. (%d,%d) ] => %d (%d seeks) %d\n", - (int)LO.pos, (int)LO.pts, (int)timebases[0], (int)fake_hi, (int)HI.pts, (int)(LO.pos - LO.back_ptr), a, LO.back_ptr); + (int)LO.pos, (int)LO.pts, (int)timebases[0], (int)HI.pos, (int)HI.pts, (int)(LO.pos - LO.back_ptr), a, LO.back_ptr); // at this point, s[i].pts < P < s[i+1].pts, and s[i].seen_next is set *start = LO.pos - LO.back_ptr; *end = HI.pos; @@ -1520,6 +1539,7 @@ nut->dopts = *dopts; nut->seek_status = 0; nut->before_seek = 0; + nut->binary_guess = 0; nut->last_syncpoint = 0; nut->find_syncpoint_state = (struct find_syncpoint_state_s){0,0,0,0}; Modified: trunk/libnut/priv.h ============================================================================== --- trunk/libnut/priv.h (original) +++ trunk/libnut/priv.h Fri Jan 26 17:28:56 2007 @@ -155,6 +155,7 @@ off_t before_seek; // position before any seek mess off_t seek_status; + off_t binary_guess; double seek_time_pos; syncpoint_list_t syncpoints;