diff options
author | Robin Gareus <robin@gareus.org> | 2012-10-13 23:27:40 +0000 |
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committer | Robin Gareus <robin@gareus.org> | 2012-10-13 23:27:40 +0000 |
commit | 4a17dd8fb619e7c8d25843c79a662f29b90ce83c (patch) | |
tree | 8196349a5c93668075bb31c67a16c2e957edf908 /libs/ardour/session_time.cc | |
parent | 13d23f15aa334971e39fe22fed30cf968e2583e8 (diff) |
move sample/timecode conversion to libtimecode.
git-svn-id: svn://localhost/ardour2/branches/3.0@13266 d708f5d6-7413-0410-9779-e7cbd77b26cf
Diffstat (limited to 'libs/ardour/session_time.cc')
-rw-r--r-- | libs/ardour/session_time.cc | 200 |
1 files changed, 18 insertions, 182 deletions
diff --git a/libs/ardour/session_time.cc b/libs/ardour/session_time.cc index 5de0055a0d..9a1507831c 100644 --- a/libs/ardour/session_time.cc +++ b/libs/ardour/session_time.cc @@ -100,194 +100,30 @@ Session::sync_time_vars () void Session::timecode_to_sample( Timecode::Time& timecode, framepos_t& sample, bool use_offset, bool use_subframes ) const { - double my_frames_per_timecode_frame = _frames_per_timecode_frame; - if (timecode.rate > 0) { - my_frames_per_timecode_frame = (double) _current_frame_rate / (double) timecode.rate; - } + timecode.rate = timecode_frames_per_second(); - if (timecode.drop) { - // The drop frame format was created to better approximate the 30000/1001 = 29.97002997002997.... - // framerate of NTSC color TV. The used frame rate of drop frame is 29.97, which drifts by about - // 0.108 frame per hour, or about 1.3 frames per 12 hours. This is not perfect, but a lot better - // than using 30 non drop, which will drift with about 1.8 frame per minute. - // Using 29.97, drop frame real time can be accurate only every 10th minute (10 minutes of 29.97 fps - // is exactly 17982 frames). One minute is 1798.2 frames, but we count 30 frames per second - // (30 * 60 = 1800). This means that at the first minute boundary (at the end of 0:0:59:29) we - // are 1.8 frames too late relative to real time. By dropping 2 frames (jumping to 0:1:0:2) we are - // approx. 0.2 frames too early. This adds up with 0.2 too early for each minute until we are 1.8 - // frames too early at 0:9:0:2 (9 * 0.2 = 1.8). The 10th minute brings us 1.8 frames later again - // (at end of 0:9:59:29), which sums up to 0 (we are back to zero at 0:10:0:0 :-). - // - // In table form: - // - // Timecode value frames offset subframes offset seconds (rounded) 44100 sample (rounded) - // 0:00:00:00 0.0 0 0.000 0 (accurate) - // 0:00:59:29 1.8 144 60.027 2647177 - // 0:01:00:02 -0.2 -16 60.060 2648648 - // 0:01:59:29 1.6 128 120.020 5292883 - // 0:02:00:02 -0.4 -32 120.053 5294354 - // 0:02:59:29 1.4 112 180.013 7938588 - // 0:03:00:02 -0.6 -48 180.047 7940060 - // 0:03:59:29 1.2 96 240.007 10584294 - // 0:04:00:02 -0.8 -64 240.040 10585766 - // 0:04:59:29 1.0 80 300.000 13230000 - // 0:05:00:02 -1.0 -80 300.033 13231471 - // 0:05:59:29 0.8 64 359.993 15875706 - // 0:06:00:02 -1.2 -96 360.027 15877177 - // 0:06:59:29 0.6 48 419.987 18521411 - // 0:07:00:02 -1.4 -112 420.020 18522883 - // 0:07:59:29 0.4 32 478.980 21167117 - // 0:08:00:02 -1.6 -128 480.013 21168589 - // 0:08:59:29 0.2 16 539.973 23812823 - // 0:09:00:02 -1.8 -144 540.007 23814294 - // 0:09:59:29 0.0+ 0+ 599.967 26458529 - // 0:10:00:00 0.0 0 600.000 26460000 (accurate) - // - // Per Sigmond <per@sigmond.no> - - // Samples inside time dividable by 10 minutes (real time accurate) - framecnt_t base_samples = (framecnt_t) (((timecode.hours * 107892) + ((timecode.minutes / 10) * 17982)) * my_frames_per_timecode_frame); - - // Samples inside time exceeding the nearest 10 minutes (always offset, see above) - int32_t exceeding_df_minutes = timecode.minutes % 10; - int32_t exceeding_df_seconds = (exceeding_df_minutes * 60) + timecode.seconds; - int32_t exceeding_df_frames = (30 * exceeding_df_seconds) + timecode.frames - (2 * exceeding_df_minutes); - framecnt_t exceeding_samples = (framecnt_t) rint(exceeding_df_frames * my_frames_per_timecode_frame); - sample = base_samples + exceeding_samples; - } else { - /* - Non drop is easy.. just note the use of - rint(timecode.rate) * _frames_per_timecode_frame - (frames per Timecode second), which is larger than - frame_rate() in the non-integer Timecode rate case. - */ - - sample = (framecnt_t)rint((((timecode.hours * 60 * 60) + (timecode.minutes * 60) + timecode.seconds) * (rint(timecode.rate) * my_frames_per_timecode_frame)) + (timecode.frames * my_frames_per_timecode_frame)); - } - - if (use_subframes) { - sample += (int32_t) (((double)timecode.subframes * my_frames_per_timecode_frame) / config.get_subframes_per_frame()); - } - - if (use_offset) { - if (config.get_timecode_offset_negative()) { - if (sample >= config.get_timecode_offset()) { - sample -= config.get_timecode_offset(); - } else { - /* Prevent song-time from becoming negative */ - sample = 0; - } - } else { - if (timecode.negative) { - if (sample <= config.get_timecode_offset()) { - sample = config.get_timecode_offset() - sample; - } else { - sample = 0; - } - } else { - sample += config.get_timecode_offset(); - } - } - } + Timecode::timecode_to_sample( + timecode, sample, use_offset, use_subframes, + _current_frame_rate, + config.get_subframes_per_frame(), + config.get_timecode_offset_negative(), config.get_timecode_offset() + ); } - void Session::sample_to_timecode (framepos_t sample, Timecode::Time& timecode, bool use_offset, bool use_subframes ) const { - framepos_t offset_sample; - - if (!use_offset) { - offset_sample = sample; - timecode.negative = false; - } else { - if (config.get_timecode_offset_negative()) { - offset_sample = sample + config.get_timecode_offset (); - timecode.negative = false; - } else { - if (sample < config.get_timecode_offset()) { - offset_sample = (config.get_timecode_offset() - sample); - timecode.negative = true; - } else { - offset_sample = sample - config.get_timecode_offset(); - timecode.negative = false; - } - } - } - - double timecode_frames_left_exact; - double timecode_frames_fraction; - uint32_t timecode_frames_left; - - // Extract whole hours. Do this to prevent rounding errors with - // high sample numbers in the calculations that follow. - timecode.hours = offset_sample / _frames_per_hour; - offset_sample = offset_sample % _frames_per_hour; - - // Calculate exact number of (exceeding) timecode frames and fractional frames - timecode_frames_left_exact = (double) offset_sample / _frames_per_timecode_frame; - timecode_frames_fraction = timecode_frames_left_exact - floor( timecode_frames_left_exact ); - timecode.subframes = (int32_t) rint(timecode_frames_fraction * config.get_subframes_per_frame()); - - // XXX Not sure if this is necessary anymore... - if (timecode.subframes == config.get_subframes_per_frame()) { - // This can happen with 24 fps (and 29.97 fps ?) - timecode_frames_left_exact = ceil( timecode_frames_left_exact ); - timecode.subframes = 0; - } - - // Extract hour-exceeding frames for minute, second and frame calculations - timecode_frames_left = (uint32_t) floor (timecode_frames_left_exact); - - if (timecode_drop_frames()) { - // See int32_t explanation in timecode_to_sample()... - - // Number of 10 minute chunks - timecode.minutes = (timecode_frames_left / 17982) * 10; // exactly 17982 frames in 10 minutes - // frames exceeding the nearest 10 minute barrier - int32_t exceeding_df_frames = timecode_frames_left % 17982; - - // Find minutes exceeding the nearest 10 minute barrier - if (exceeding_df_frames >= 1800) { // nothing to do if we are inside the first minute (0-1799) - exceeding_df_frames -= 1800; // take away first minute (different number of frames than the others) - int32_t extra_minutes_minus_1 = exceeding_df_frames / 1798; // how many minutes after the first one - exceeding_df_frames -= extra_minutes_minus_1 * 1798; // take away the (extra) minutes just found - timecode.minutes += extra_minutes_minus_1 + 1; // update with exceeding minutes - } + Timecode::sample_to_timecode ( + sample, timecode, use_offset, use_subframes, - // Adjust frame numbering for dropped frames (frame 0 and 1 skipped at start of every minute except every 10th) - if (timecode.minutes % 10) { - // Every minute except every 10th - if (exceeding_df_frames < 28) { - // First second, frames 0 and 1 are skipped - timecode.seconds = 0; - timecode.frames = exceeding_df_frames + 2; - } else { - // All other seconds, all 30 frames are counted - exceeding_df_frames -= 28; - timecode.seconds = (exceeding_df_frames / 30) + 1; - timecode.frames = exceeding_df_frames % 30; - } - } else { - // Every 10th minute, all 30 frames counted in all seconds - timecode.seconds = exceeding_df_frames / 30; - timecode.frames = exceeding_df_frames % 30; - } - } else { - // Non drop is easy - timecode.minutes = timecode_frames_left / ((int32_t) rint (timecode_frames_per_second ()) * 60); - timecode_frames_left = timecode_frames_left % ((int32_t) rint (timecode_frames_per_second ()) * 60); - timecode.seconds = timecode_frames_left / (int32_t) rint(timecode_frames_per_second ()); - timecode.frames = timecode_frames_left % (int32_t) rint(timecode_frames_per_second ()); - } + timecode_frames_per_second(), + timecode_drop_frames(), + double(_current_frame_rate), - if (!use_subframes) { - timecode.subframes = 0; - } - /* set frame rate and drop frame */ - timecode.rate = timecode_frames_per_second (); - timecode.drop = timecode_drop_frames(); + config.get_subframes_per_frame(), + config.get_timecode_offset_negative(), config.get_timecode_offset() + ); } void @@ -298,7 +134,7 @@ Session::timecode_time (framepos_t when, Timecode::Time& timecode) return; } - sample_to_timecode( when, timecode, true /* use_offset */, false /* use_subframes */ ); + this->sample_to_timecode( when, timecode, true /* use_offset */, false /* use_subframes */ ); last_timecode_when = when; last_timecode = timecode; @@ -313,7 +149,7 @@ Session::timecode_time_subframes (framepos_t when, Timecode::Time& timecode) return; } - sample_to_timecode( when, timecode, true /* use_offset */, true /* use_subframes */ ); + this->sample_to_timecode( when, timecode, true /* use_offset */, true /* use_subframes */ ); last_timecode_when = when; last_timecode = timecode; @@ -323,7 +159,7 @@ Session::timecode_time_subframes (framepos_t when, Timecode::Time& timecode) void Session::timecode_duration (framecnt_t when, Timecode::Time& timecode) const { - sample_to_timecode( when, timecode, false /* use_offset */, true /* use_subframes */ ); + this->sample_to_timecode( when, timecode, false /* use_offset */, true /* use_subframes */ ); } void |