From ded68fb10275c9f9a66e7019171b83cab0e9485d Mon Sep 17 00:00:00 2001
From: Sebastian Parborg <darkdefende@gmail.com>
Date: Tue, 6 Jul 2021 19:48:06 +0200
Subject: VSE: Fix audaspace not reading ffmpeg files with start offset
 correctly

The duration and start time for audio strips were not correctly read in
audaspace.

Some video files have a "lead in" section of audio that plays before the
video starts playing back. Before this patch, we would play this lead in
audio at the same time as the video started and thus the audio would not
be in sync anymore.

Now the lead in audio is cut off and the duration should be correctly
calculated with this in mind.

If the audio starts after the video, the audio strip is shifted to
account for this, but it will also lead to cut off audio which might not
be wanted. However we don't have a simple way to solve this at this
point.

Differential Revision: http://developer.blender.org/D11917
---
 source/blender/editors/space_sequencer/sequencer_add.c  | 16 ++++++++++------
 source/blender/editors/space_sequencer/sequencer_draw.c | 10 ++++++----
 2 files changed, 16 insertions(+), 10 deletions(-)

(limited to 'source/blender/editors/space_sequencer')

diff --git a/source/blender/editors/space_sequencer/sequencer_add.c b/source/blender/editors/space_sequencer/sequencer_add.c
index 47495eaa57a..ff8cbdb1a59 100644
--- a/source/blender/editors/space_sequencer/sequencer_add.c
+++ b/source/blender/editors/space_sequencer/sequencer_add.c
@@ -643,15 +643,17 @@ static void sequencer_add_movie_multiple_strips(bContext *C,
     BLI_strncpy(load_data->name, file_only, sizeof(load_data->name));
     Sequence *seq_movie = NULL;
     Sequence *seq_sound = NULL;
+    double video_start_offset;
+
     load_data->channel++;
-    seq_movie = SEQ_add_movie_strip(bmain, scene, ed->seqbasep, load_data);
+    seq_movie = SEQ_add_movie_strip(bmain, scene, ed->seqbasep, load_data, &video_start_offset);
     load_data->channel--;
     if (seq_movie == NULL) {
       BKE_reportf(op->reports, RPT_ERROR, "File '%s' could not be loaded", load_data->path);
     }
     else {
       if (RNA_boolean_get(op->ptr, "sound")) {
-        seq_sound = SEQ_add_sound_strip(bmain, scene, ed->seqbasep, load_data);
+        seq_sound = SEQ_add_sound_strip(bmain, scene, ed->seqbasep, load_data, video_start_offset);
       }
       load_data->start_frame += seq_movie->enddisp - seq_movie->startdisp;
       seq_load_apply_generic_options(C, op, seq_sound);
@@ -670,8 +672,10 @@ static bool sequencer_add_movie_single_strip(bContext *C, wmOperator *op, SeqLoa
 
   Sequence *seq_movie = NULL;
   Sequence *seq_sound = NULL;
+  double video_start_offset;
+
   load_data->channel++;
-  seq_movie = SEQ_add_movie_strip(bmain, scene, ed->seqbasep, load_data);
+  seq_movie = SEQ_add_movie_strip(bmain, scene, ed->seqbasep, load_data, &video_start_offset);
   load_data->channel--;
 
   if (seq_movie == NULL) {
@@ -679,7 +683,7 @@ static bool sequencer_add_movie_single_strip(bContext *C, wmOperator *op, SeqLoa
     return false;
   }
   if (RNA_boolean_get(op->ptr, "sound")) {
-    seq_sound = SEQ_add_sound_strip(bmain, scene, ed->seqbasep, load_data);
+    seq_sound = SEQ_add_sound_strip(bmain, scene, ed->seqbasep, load_data, video_start_offset);
   }
   seq_load_apply_generic_options(C, op, seq_sound);
   seq_load_apply_generic_options(C, op, seq_movie);
@@ -822,7 +826,7 @@ static void sequencer_add_sound_multiple_strips(bContext *C,
     RNA_string_get(&itemptr, "name", file_only);
     BLI_join_dirfile(load_data->path, sizeof(load_data->path), dir_only, file_only);
     BLI_strncpy(load_data->name, file_only, sizeof(load_data->name));
-    Sequence *seq = SEQ_add_sound_strip(bmain, scene, ed->seqbasep, load_data);
+    Sequence *seq = SEQ_add_sound_strip(bmain, scene, ed->seqbasep, load_data, 0.0f);
     if (seq == NULL) {
       BKE_reportf(op->reports, RPT_ERROR, "File '%s' could not be loaded", load_data->path);
     }
@@ -840,7 +844,7 @@ static bool sequencer_add_sound_single_strip(bContext *C, wmOperator *op, SeqLoa
   Scene *scene = CTX_data_scene(C);
   Editing *ed = SEQ_editing_get(scene, true);
 
-  Sequence *seq = SEQ_add_sound_strip(bmain, scene, ed->seqbasep, load_data);
+  Sequence *seq = SEQ_add_sound_strip(bmain, scene, ed->seqbasep, load_data, 0.0f);
   if (seq == NULL) {
     BKE_reportf(op->reports, RPT_ERROR, "File '%s' could not be loaded", load_data->path);
     return false;
diff --git a/source/blender/editors/space_sequencer/sequencer_draw.c b/source/blender/editors/space_sequencer/sequencer_draw.c
index 0472e1264ce..e49a88c88d2 100644
--- a/source/blender/editors/space_sequencer/sequencer_draw.c
+++ b/source/blender/editors/space_sequencer/sequencer_draw.c
@@ -284,10 +284,12 @@ static void draw_seq_waveform_overlay(View2D *v2d,
       return;
     }
 
-    startsample = floor((seq->startofs + seq->anim_startofs) / FPS *
-                        SOUND_WAVE_SAMPLES_PER_SECOND);
-    endsample = ceil((seq->startofs + seq->anim_startofs + seq->enddisp - seq->startdisp) / FPS *
-                     SOUND_WAVE_SAMPLES_PER_SECOND);
+    startsample = (seq->startofs + seq->anim_startofs) / FPS * SOUND_WAVE_SAMPLES_PER_SECOND;
+    startsample += seq->sound->offset_time * SOUND_WAVE_SAMPLES_PER_SECOND;
+
+    endsample = (seq->enddisp - seq->startdisp) / FPS * SOUND_WAVE_SAMPLES_PER_SECOND;
+    endsample += startsample;
+
     samplestep = (endsample - startsample) * stepsize / (x2 - x1);
 
     length = min_ii(
-- 
cgit v1.2.3