Frame Dropping vs AV-Sync?

Question

What exactly is the difference between the Frame Dropping and AV-Sync options?
I understand that they both drop frames in order to make the playback closer to real-time in the 3D view, but how does AV-sync make it more synced to the sound than frame dropping, if they're both just dropping frames to get the correct frame rate? Is there any time when I should use frame dropping instead of AV-Sync, if they both get the correct frame rate?

I cannot give an answer but guess that Frame Dropping may not play audio back in perfect sync? Perhaps it allows audio sync to drift? — 3pointedit, Dec 31 '15 at 04:19

score 3 · Answer 1 · answered Jan 20 '16 at 23:33

As far as I can see:

No Sync just tries to play back every single Frame no matter if it causes lags or time shifting problems with the Audio or the actual physical time.
Frame Dropping drops Frames from the ViewPort Animation Playback to match up with the actual Frame Rate being used
AV Sync skips Frames from Video Footage in the VSE so that Audio and Video in the Image Preview Sequencer Mode stays in sync

score 0 · Accepted Answer · answered Dec 31 '15 at 11:08

0

Let's say we have a video file with sound and we are playing at lower fps than the original. Blender shows every frame while playing, meaning the video will get behind the sound (sound plays at original speed).

AV-sync means Blender will skip (video) frames when video is delayed on the audio.

Frame-dropping does drop frames to stay at target fps (performance issues etc.)

answered Dec 31 '15 at 11:08

Jaroslav Jerryno Novotny

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I understand that they both skip/drop frames. But if they are both dropping frames, what's the difference? – markasoftware Jan 01 '16 at 00:32
@Markasoftware I just described the difference. They drop different frames and differently. Can you specify what is not clear or how to make the answer better undestood? thx. – Jaroslav Jerryno Novotny Jan 01 '16 at 08:59

score -2 · Answer 3 · answered Jan 08 '16 at 17:33

-2

av sync drops frames from the sound. frame dropping drops frames of the animation/video.

answered Jan 08 '16 at 17:33

Lahiru VP

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Please add more to your answer. – David Jan 08 '16 at 18:39
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AV Sync doesn't drop frames from the sound, I'm pretty sure. First of all, sound doesn't have frames in the same way that video does (I think), and secondly when playing back things with AV sync the audio has almost always sounded perfect – markasoftware Jan 09 '16 at 00:13

Frame Dropping vs AV-Sync?

3 Answers3