diff options
author | Paul Davis <paul@linuxaudiosystems.com> | 2017-09-18 13:19:12 -0400 |
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committer | Paul Davis <paul@linuxaudiosystems.com> | 2017-09-18 13:19:12 -0400 |
commit | 7a477fb9d6337f903b91fa26465e252e3845ec4d (patch) | |
tree | 13a9157503b6cabd583cb35372ef319b1385df9f /libs/timecode | |
parent | 30b087ab3d28f1585987fa3f6ae006562ae192e3 (diff) |
manually fix up comments in libs/timecode/src/time.cc that got edited by f2s
Diffstat (limited to 'libs/timecode')
-rw-r--r-- | libs/timecode/src/time.cc | 40 |
1 files changed, 20 insertions, 20 deletions
diff --git a/libs/timecode/src/time.cc b/libs/timecode/src/time.cc index 7d3815f858..c37f3aa680 100644 --- a/libs/timecode/src/time.cc +++ b/libs/timecode/src/time.cc @@ -274,7 +274,7 @@ decrement_subframes (Time& timecode, uint32_t subframes_per_frame) } -/** Go to next whole second (samples == 0 or samples == 2) */ +/** Go to next whole second (frames == 0 or frames == 2) */ Wrap increment_seconds (Time& timecode, uint32_t subframes_per_frame) { @@ -286,13 +286,13 @@ increment_seconds (Time& timecode, uint32_t subframes_per_frame) if (timecode.negative) { // Wrap second if on second boundary wrap = increment (timecode, subframes_per_frame); - // Go to lowest absolute sample value + // Go to lowest absolute frame value seconds_floor (timecode); if (Timecode_IS_ZERO (timecode)) { timecode.negative = false; } } else { - // Go to highest possible sample in this second + // Go to highest possible frame 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 sample + // Increment by one frame wrap = increment (timecode, subframes_per_frame); } @@ -316,7 +316,7 @@ increment_seconds (Time& timecode, uint32_t subframes_per_frame) } -/** Go to lowest (absolute) sample value in this second +/** Go to lowest (absolute) frame value in this second * Doesn't care about positive/negative */ void seconds_floor (Time& timecode) @@ -324,7 +324,7 @@ seconds_floor (Time& timecode) // Clear subframes frames_floot (timecode); - // Go to lowest possible sample in this second + // Go to lowest possible frame in this second switch ((int)ceil (timecode.rate)) { case 24: case 25: @@ -348,7 +348,7 @@ seconds_floor (Time& timecode) } -/** Go to next whole minute (seconds == 0, samples == 0 or samples == 2) */ +/** Go to next whole minute (seconds == 0, frames == 0 or frames == 2) */ Wrap increment_minutes (Time& timecode, uint32_t subframes_per_frame) { @@ -379,7 +379,7 @@ minutes_floor (Time& timecode) { // Go to lowest possible second timecode.seconds = 0; - // Go to lowest possible sample + // Go to lowest possible frame seconds_floor (timecode); if (Timecode_IS_ZERO (timecode)) { @@ -388,7 +388,7 @@ minutes_floor (Time& timecode) } -/** Go to next whole hour (minute = 0, second = 0, sample = 0) */ +/** Go to next whole hour (minute = 0, second = 0, frame = 0) */ Wrap increment_hours (Time& timecode, uint32_t subframes_per_frame) { @@ -656,21 +656,21 @@ timecode_to_sample( const double samples_per_timecode_frame = (double) sample_sample_rate / (double) timecode.rate; if (timecode.drop) { - // 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 + // 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 fra,e 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 samples). One minute is 1798.2 samples, 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 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 + // are 1.8 framess 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 + // samples 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 samples offset subframes offset seconds (rounded) 44100 sample (rounded) + // 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 @@ -712,7 +712,7 @@ timecode_to_sample( /* Non drop is easy.. just note the use of rint(timecode.rate) * samples_per_timecode_frame - (samples per Timecode second), which is larger than + (frames per Timecode second), which is larger than sample_rate() in the non-integer Timecode rate case. */ |