diff options
Diffstat (limited to 'libs/timecode/src/time.cc')
| -rw-r--r-- | libs/timecode/src/time.cc | 80 |
1 files changed, 40 insertions, 40 deletions
diff --git a/libs/timecode/src/time.cc b/libs/timecode/src/time.cc index b833878255..7d3815f858 100644 --- a/libs/timecode/src/time.cc +++ b/libs/timecode/src/time.cc @@ -30,7 +30,7 @@ namespace Timecode { double Time::default_rate = 30.0; -/** Increment @a timecode by exactly one frame (keep subframes value). +/** Increment @a timecode by exactly one sample (keep subframes value). * Realtime safe. * @return true if seconds wrap. */ @@ -117,7 +117,7 @@ increment (Time& timecode, uint32_t subframes_per_frame) } -/** Decrement @a timecode by exactly one frame (keep subframes value) +/** Decrement @a timecode by exactly one sample (keep subframes value) * Realtime safe. * @return true if seconds wrap. */ Wrap @@ -204,9 +204,9 @@ decrement (Time& timecode, uint32_t subframes_per_frame) } -/** Go to lowest absolute subframe value in this frame (set to 0 :-)) */ +/** Go to lowest absolute subframe value in this sample (set to 0 :-)) */ void -frames_floor (Time& timecode) +frames_floot (Time& timecode) { timecode.subframes = 0; if (Timecode_IS_ZERO (timecode)) { @@ -274,25 +274,25 @@ decrement_subframes (Time& timecode, uint32_t subframes_per_frame) } -/** Go to next whole second (frames == 0 or frames == 2) */ +/** Go to next whole second (samples == 0 or samples == 2) */ Wrap increment_seconds (Time& timecode, uint32_t subframes_per_frame) { Wrap wrap = NONE; // Clear subframes - frames_floor (timecode); + frames_floot (timecode); if (timecode.negative) { // Wrap second if on second boundary wrap = increment (timecode, subframes_per_frame); - // Go to lowest absolute frame value + // Go to lowest absolute sample value seconds_floor (timecode); if (Timecode_IS_ZERO (timecode)) { timecode.negative = false; } } else { - // Go to highest possible frame in this second + // Go to highest possible sample in this second switch ((int)ceil (timecode.rate)) { case 24: timecode.frames = 23; @@ -308,7 +308,7 @@ increment_seconds (Time& timecode, uint32_t subframes_per_frame) break; } - // Increment by one frame + // Increment by one sample wrap = increment (timecode, subframes_per_frame); } @@ -316,15 +316,15 @@ increment_seconds (Time& timecode, uint32_t subframes_per_frame) } -/** Go to lowest (absolute) frame value in this second +/** Go to lowest (absolute) sample value in this second * Doesn't care about positive/negative */ void seconds_floor (Time& timecode) { // Clear subframes - frames_floor (timecode); + frames_floot (timecode); - // Go to lowest possible frame in this second + // Go to lowest possible sample in this second switch ((int)ceil (timecode.rate)) { case 24: case 25: @@ -348,14 +348,14 @@ seconds_floor (Time& timecode) } -/** Go to next whole minute (seconds == 0, frames == 0 or frames == 2) */ +/** Go to next whole minute (seconds == 0, samples == 0 or samples == 2) */ Wrap increment_minutes (Time& timecode, uint32_t subframes_per_frame) { Wrap wrap = NONE; // Clear subframes - frames_floor (timecode); + frames_floot (timecode); if (timecode.negative) { // Wrap if on minute boundary @@ -379,7 +379,7 @@ minutes_floor (Time& timecode) { // Go to lowest possible second timecode.seconds = 0; - // Go to lowest possible frame + // Go to lowest possible sample seconds_floor (timecode); if (Timecode_IS_ZERO (timecode)) { @@ -388,14 +388,14 @@ minutes_floor (Time& timecode) } -/** Go to next whole hour (minute = 0, second = 0, frame = 0) */ +/** Go to next whole hour (minute = 0, second = 0, sample = 0) */ Wrap increment_hours (Time& timecode, uint32_t subframes_per_frame) { Wrap wrap = NONE; // Clear subframes - frames_floor (timecode); + frames_floot (timecode); if (timecode.negative) { // Wrap if on hour boundary @@ -612,14 +612,14 @@ std::string timecode_format_time (Timecode::Time TC) std::string timecode_format_sampletime ( int64_t sample, - double sample_frame_rate, + double sample_sample_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, + sample_sample_rate, 80, false, 0); return timecode_format_time(t); } @@ -647,30 +647,30 @@ 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 */, + double sample_sample_rate /**< may include pull up/down */, uint32_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 samples_per_timecode_frame = (double) sample_frame_rate / (double) timecode.rate; + const double samples_per_timecode_frame = (double) sample_sample_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 + // The drop sample format was created to better approximate the 30000/1001 = 29.97002997002997.... + // framerate of NTSC color TV. The used frame rate of drop sample is 29.97, which drifts by about + // 0.108 sample per hour, or about 1.3 samples per 12 hours. This is not perfect, but a lot better + // than using 30 non drop, which will drift with about 1.8 sample per minute. + // Using 29.97, drop sample real time can be accurate only every 10th minute (10 minutes of 29.97 fps + // is exactly 17982 samples). One minute is 1798.2 samples, but we count 30 samples 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 + // are 1.8 samples too late relative to real time. By dropping 2 samples (jumping to 0:1:0:2) we are + // approx. 0.2 samples too early. This adds up with 0.2 too early for each minute until we are 1.8 + // samples too early at 0:9:0:2 (9 * 0.2 = 1.8). The 10th minute brings us 1.8 samples 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) + // Timecode value samples 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 @@ -707,13 +707,13 @@ timecode_to_sample( + fps_i * 60 * timecode.minutes + fps_i * timecode.seconds + timecode.frames - 2 * (totalMinutes - totalMinutes / 10); - sample = frameNumber * sample_frame_rate / (double) timecode.rate; + sample = frameNumber * sample_sample_rate / (double) timecode.rate; } else { /* Non drop is easy.. just note the use of rint(timecode.rate) * samples_per_timecode_frame - (frames per Timecode second), which is larger than - frame_rate() in the non-integer Timecode rate case. + (samples per Timecode second), which is larger than + sample_rate() in the non-integer Timecode rate case. */ sample = (int64_t) rint( @@ -760,7 +760,7 @@ sample_to_timecode ( /* framerate info */ double timecode_frames_per_second, bool timecode_drop_frames, - double sample_frame_rate/**< can include pull up/down */, + double sample_sample_rate/**< can include pull up/down */, uint32_t subframes_per_frame, /* optional offset - can be improved: function pointer to lazily query this*/ bool offset_is_negative, int64_t offset_samples @@ -787,14 +787,14 @@ sample_to_timecode ( } if (timecode_drop_frames) { - int64_t frameNumber = floor( (double)offset_sample * timecode_frames_per_second / sample_frame_rate); + int64_t frameNumber = floor( (double)offset_sample * timecode_frames_per_second / sample_sample_rate); - /* there are 17982 frames in 10 min @ 29.97df */ + /* there are 17982 samples in 10 min @ 29.97df */ const int64_t D = frameNumber / 17982; const int64_t M = frameNumber % 17982; timecode.subframes = rint(subframes_per_frame - * ((double)offset_sample * timecode_frames_per_second / sample_frame_rate - (double)frameNumber)); + * ((double)offset_sample * timecode_frames_per_second / sample_sample_rate - (double)frameNumber)); if (timecode.subframes == subframes_per_frame) { timecode.subframes = 0; @@ -812,7 +812,7 @@ sample_to_timecode ( double timecode_frames_left_exact; double timecode_frames_fraction; int64_t timecode_frames_left; - const double samples_per_timecode_frame = sample_frame_rate / timecode_frames_per_second; + const double samples_per_timecode_frame = sample_sample_rate / timecode_frames_per_second; const int64_t frames_per_hour = (int64_t)(3600. * rint(timecode_frames_per_second) * samples_per_timecode_frame); timecode.hours = offset_sample / frames_per_hour; @@ -839,7 +839,7 @@ sample_to_timecode ( if (!use_subframes) { timecode.subframes = 0; } - /* set frame rate and drop frame */ + /* set frame rate and drop sample */ timecode.rate = timecode_frames_per_second; timecode.drop = timecode_drop_frames; } |