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Fix: Improve retiming speed get/set code precision

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Use float for intermediate values when calculating speed or timeline
frames.

More details on precision improvement itself: In some cases, setting
strip speed to say 70% would result in actual speed being set to say
69.5%. With this change, the number would be closer or equal to 70%.

There few tangentially related changes:
- `SEQ_retiming_key_speed_get` was changed so both functions work in
  same time domain.
- `SEQ_retiming_key_speed_set` now expects speed as float factor
  instead of percentage. This is consistent with get function return
   value.
- Improve variable names, for better code readability.

Pull Request: https://projects.blender.org/blender/blender/pulls/131782
This commit is contained in:
Richard Antalik
2025-02-07 22:41:18 +01:00
committed by Richard Antalik
parent f9c4ad1477
commit b2660dbd2b
2 changed files with 15 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
source/blender/editors/space_sequencer/sequencer_retiming.cc
View File

@@ -654,7 +654,7 @@ static int strip_speed_set_exec(bContext *C, const wmOperator *op)
continue;
}
/* TODO: it would be nice to multiply speed with complex retiming by a factor. */
SEQ_retiming_key_speed_set(scene, strip, key, RNA_float_get(op->ptr, "speed"), false);
SEQ_retiming_key_speed_set(scene, strip, key, RNA_float_get(op->ptr, "speed") / 100.0f, false);
ListBase *seqbase = SEQ_active_seqbase_get(SEQ_editing_get(scene));
if (SEQ_transform_test_overlap(scene, seqbase, strip)) {
@@ -679,7 +679,7 @@ static int segment_speed_set_exec(const bContext *C,
SEQ_retiming_key_speed_set(scene,
item.value,
item.key,
RNA_float_get(op->ptr, "speed"),
RNA_float_get(op->ptr, "speed") / 100.0f,
RNA_boolean_get(op->ptr, "keep_retiming"));
if (SEQ_transform_test_overlap(scene, seqbase, item.value)) {

32
source/blender/sequencer/intern/strip_retiming.cc
View File

@@ -781,17 +781,12 @@ float SEQ_retiming_key_speed_get(const Strip *strip, const SeqRetimingKey *key)
}
const SeqRetimingKey *key_prev = key - 1;
const int frame_index_max = strip->len - 1;
const int frame_retimed_prev = round_fl_to_int(key_prev->retiming_factor * frame_index_max);
const int frame_index_prev = key_prev->strip_frame_index;
const int frame_retimed = round_fl_to_int(key->retiming_factor * frame_index_max);
const int frame_index = key->strip_frame_index;
const int fragment_length_retimed = frame_retimed - frame_retimed_prev;
const int fragment_length_original = frame_index - frame_index_prev;
const float speed = float(fragment_length_retimed) / float(fragment_length_original);
const float frame_index_start = round_fl_to_int(key_prev->retiming_factor * frame_index_max);
const float frame_index_end = round_fl_to_int(key->retiming_factor * frame_index_max);
const float segment_content_frame_count = frame_index_end - frame_index_start;
const float segment_length = key->strip_frame_index - key_prev->strip_frame_index;
const float speed = segment_content_frame_count / segment_length;
return speed;
}
@@ -803,19 +798,18 @@ void SEQ_retiming_key_speed_set(
}
const SeqRetimingKey *key_prev = key - 1;
const float speed_fac = 100.0f / speed;
const int frame_index_max = strip->len - 1;
const int frame_retimed_prev = round_fl_to_int(key_prev->retiming_factor * frame_index_max);
const int frame_retimed = round_fl_to_int(key->retiming_factor * frame_index_max);
const float frame_index_prev = round_fl_to_int(key_prev->retiming_factor * frame_index_max);
const float frame_index = round_fl_to_int(key->retiming_factor * frame_index_max);
const int segment_duration = (frame_retimed - frame_retimed_prev) /
SEQ_time_media_playback_rate_factor_get(scene, strip);
const int new_duration = segment_duration * speed_fac;
const float segment_timeline_duration = (frame_index - frame_index_prev) /
SEQ_time_media_playback_rate_factor_get(scene, strip);
const float new_timeline_duration = segment_timeline_duration / speed;
const int orig_timeline_frame = SEQ_retiming_key_timeline_frame_get(scene, strip, key);
const int new_timeline_frame = SEQ_retiming_key_timeline_frame_get(scene, strip, key_prev) +
new_duration;
const float orig_timeline_frame = SEQ_retiming_key_timeline_frame_get(scene, strip, key);
const float new_timeline_frame = std::round(
SEQ_retiming_key_timeline_frame_get(scene, strip, key_prev) + new_timeline_duration);
SEQ_retiming_key_timeline_frame_set(scene, strip, key, new_timeline_frame);