From 4a17dd8fb619e7c8d25843c79a662f29b90ce83c Mon Sep 17 00:00:00 2001 From: Robin Gareus Date: Sat, 13 Oct 2012 23:27:40 +0000 Subject: move sample/timecode conversion to libtimecode. git-svn-id: svn://localhost/ardour2/branches/3.0@13266 d708f5d6-7413-0410-9779-e7cbd77b26cf --- libs/timecode/src/time.cc | 243 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 243 insertions(+) (limited to 'libs/timecode/src/time.cc') diff --git a/libs/timecode/src/time.cc b/libs/timecode/src/time.cc index cc687d492b..7e8b94c121 100644 --- a/libs/timecode/src/time.cc +++ b/libs/timecode/src/time.cc @@ -20,6 +20,7 @@ #define Timecode_IS_ZERO(sm) (!(sm).frames && !(sm).seconds && !(sm).minutes && !(sm).hours && !(sm.subframes)) #include +#include #include "timecode/time.h" @@ -577,6 +578,248 @@ timecode_format_name (TimecodeFormat const t) return "??"; } +std::string timecode_format_time (Timecode::Time& TC) +{ + char buf[32]; + if (TC.negative) { + snprintf (buf, sizeof (buf), "-%02" PRIu32 ":%02" PRIu32 ":%02" PRIu32 ":%02" PRIu32, TC.hours, TC.minutes, TC.seconds, TC.frames); + } else { + snprintf (buf, sizeof (buf), " %02" PRIu32 ":%02" PRIu32 ":%02" PRIu32 ":%02" PRIu32, TC.hours, TC.minutes, TC.seconds, TC.frames); + } + return std::string(buf); +} + +std::string timecode_format_sampletime ( + int64_t sample, + double sample_frame_rate, + double timecode_frames_per_second, bool timecode_drop_frames) +{ + Time t; + sample_to_timecode( + sample, t, false, false, + timecode_frames_per_second, timecode_drop_frames, + sample_frame_rate, + 80, false, 0); + return timecode_format_time(t); +} + +void +timecode_to_sample( + Timecode::Time& timecode, int64_t& sample, + bool use_offset, bool use_subframes, + /* Note - framerate info is taken from Timecode::Time& */ + double sample_frame_rate /**< may include pull up/down */, + int32_t subframes_per_frame, + /* optional offset - can be improved: function pointer to lazily query this*/ + bool offset_is_negative, int64_t offset_samples + ) +{ + const double frames_per_timecode_frame = (double) sample_frame_rate / (double) timecode.rate; + + 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 + + // Samples inside time dividable by 10 minutes (real time accurate) + int64_t base_samples = (int64_t) (((timecode.hours * 107892) + ((timecode.minutes / 10) * 17982)) * 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); + int64_t exceeding_samples = (int64_t) rint(exceeding_df_frames * 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 = (int64_t)rint((((timecode.hours * 60 * 60) + (timecode.minutes * 60) + timecode.seconds) * (rint(timecode.rate) * frames_per_timecode_frame)) + (timecode.frames * frames_per_timecode_frame)); + } + + if (use_subframes) { + sample += (int64_t) (((double)timecode.subframes * frames_per_timecode_frame) / subframes_per_frame); + } + + if (use_offset) { + if (offset_is_negative) { + if (sample >= offset_samples) { + sample -= offset_samples; + } else { + /* Prevent song-time from becoming negative */ + sample = 0; + } + } else { + if (timecode.negative) { + if (sample <= offset_samples) { + sample = offset_samples - sample; + } else { + sample = 0; + } + } else { + sample += offset_samples; + } + } + } +} + + +void +sample_to_timecode ( + int64_t sample, Timecode::Time& timecode, + bool use_offset, bool use_subframes, + /* framerate info */ + double timecode_frames_per_second, + bool timecode_drop_frames, + double sample_frame_rate/**< can include pull up/down */, + int32_t subframes_per_frame, + /* optional offset - can be improved: function pointer to lazily query this*/ + bool offset_is_negative, int64_t offset_samples + ) +{ + const double frames_per_timecode_frame = (double) sample_frame_rate / (double) timecode_frames_per_second; + int32_t frames_per_hour; + + if (timecode_drop_frames) { + frames_per_hour = (int32_t)(107892 * frames_per_timecode_frame); + } else { + frames_per_hour = (int32_t)(3600 * rint(timecode_frames_per_second) * frames_per_timecode_frame); + } + + /* do the work */ + int64_t offset_sample; + + if (!use_offset) { + offset_sample = sample; + timecode.negative = false; + } else { + if (offset_is_negative) { + offset_sample = sample + offset_samples; + timecode.negative = false; + } else { + if (sample < offset_samples) { + offset_sample = (offset_samples - sample); + timecode.negative = true; + } else { + offset_sample = sample - offset_samples; + timecode.negative = false; + } + } + } + + double timecode_frames_left_exact; + double timecode_frames_fraction; + uint64_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) floor(timecode_frames_fraction * subframes_per_frame); + + // XXX Not sure if this is necessary anymore... + if (timecode.subframes == 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 = (uint64_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 + } + + // 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); + } + + if (!use_subframes) { + timecode.subframes = 0; + } + /* set frame rate and drop frame */ + timecode.rate = timecode_frames_per_second; + timecode.drop = timecode_drop_frames; +} + } // namespace Timecode std::ostream& -- cgit v1.2.3