PD Render Inserts Silence at 30fps, not at 24

V1v10

Newbie Joined: Oct 17, 2015 20:46 Messages: 25 Offline

Solved by

Oct 17, 2015 20:58

Hey Folks,

I'm new to PD, but have been editing video for a while, and I'm liking what I get. But tonight I've got a strange problem. I've got 720 video from a little action cam that I'm putting together, and this thing doesn't shoot files of duration longer than 5 minutes at a time. It auto-chunks them.

NP, I figure, just butt-end them in the timeline. However, in a few transitions, when using preview, I get a moment of silence between the clips. When I zoom in, the audio track thumb shows audio the whole way. Opening the audio from each file in Audio director shows audio the whole way. I decide it's just playback artifact, and quickly highlight and produce that little transition, just to be sure.

Nope. Outputting it at 1280x720 (same as original) in WMV at 30 fps (same as original) gives me a moment of silence in between. Attached is an image of the audio track from both the 24 fps render and the 30fps, the flatline silence clearly visible in the 30.

I experimented with MP4 at both 24 fps and 30, and the audio seemed to do fine there too.

I guess I want to know if there's a reason the 30fps WMV render would be inserting this silent gap (and it did it a dozen times) or if this looks like a bug. I find it especially odd since the original video is 30 fps.

Anyone seen this or have any ideas?


Filename	wmv30sound.JPG	Download
Description	audio at 30 fps
Filesize	218 Kbytes
Downloaded:	36 time(s)


Filename	wmv24sound.JPG	Download
Description	audio at 24 fps
Filesize	224 Kbytes
Downloaded:	29 time(s)

JL_JL

Senior Contributor Location: Arizona, USA Joined: Oct 01, 2006 20:01 Messages: 6091 Offline

Oct 17, 2015 22:18

PD has been known to periodically have issue with this for some cameras, usually the cheaper lower end point and shoot type.

Are you DOS literate? If so one can add all files together and most of the time PD is happier and this often results in no audio glitch between clips. The DOS command would be like: copy /b file1.m2ts+file2.m2ts newfile.m2ts

tsMuxerGUI.exe also works good for that task too.

Often some camera models also come with software to stitch the clips together too.

Jeff

V1v10

Newbie Joined: Oct 17, 2015 20:46 Messages: 25 Offline

Oct 18, 2015 08:36

Yeah, this is a cheap polaroid cube. For the price, it's quite handy, especially since it's so small and light, and has that built-in magnet, that you can hack together a mount and put it anywhere -- like on the brim of a hat. Downside is that footage is so-so, and files aren't great.

Never occurred to me to try stitching them from a command prompt. It'll be nice to DOS it up. I don't do that so much anymore.

Still seems strange to me that it would happen only on one frame rate for one file type, but what do I know.

V1v10

Newbie Joined: Oct 17, 2015 20:46 Messages: 25 Offline

Oct 18, 2015 09:01

Doh, splicing together with command line doesn't seem to work with these files. (They are MOVs). OS appears to append them, and file size = sum of individual files, but resulting file has length in header = to one of the files, and any vid player I try (along with PD) only plays the first file's length of combined file, then stops as it believes it's at the end of the file.

... and tsMuxer won't handle them either. Throws error messages (loads files anyway) but doesn't concatenate them.

Unless I can figure another way to splice these together without producing/reproducing, I may be stuck having to play the format/frame rate game to get PD to handle these properly. Maybe concatenate them in PD at whatever format and frame rate seems to yield the right sound and best picture, then use those combined files for my edit.

This message was edited 1 time. Last update was at Oct 18. 2015 09:15

Julien Pierre

Contributor Joined: Apr 14, 2011 01:34 Messages: 476 Offline

Oct 18, 2015 09:30

V1v10, why not file a bug with Cyberlink ?

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JL_JL

Senior Contributor Location: Arizona, USA Joined: Oct 01, 2006 20:01 Messages: 6091 Offline

Oct 18, 2015 09:54

Quote: Doh, splicing together with command line doesn't seem to work with these files. (They are MOVs). OS appears to append them, and file size = sum of individual files, but resulting file has length in header = to one of the files, and any vid player I try (along with PD) only plays the first file's length of combined file, then stops as it believes it's at the end of the file.

... and tsMuxer won't handle them either. Throws error messages (loads files anyway) but doesn't concatenate them.

Unless I can figure another way to splice these together without producing/reproducing, I may be stuck having to play the format/frame rate game to get PD to handle these properly. Maybe concatenate them in PD at whatever format and frame rate seems to yield the right sound and best picture, then use those combined files for my edit.

Oh, MOV files, yes, a transport stream (tsMuxer) won't help much then, neither simple file concatenation. Can you post a ~10sec clip straight off the camera to experiment with, maybe something else might become apparent.

Another suggestion would be FormatFactory, free and fairly robust with many file conversions, to convert into a format that PD handles okay.

Jeff

V1v10

Newbie Joined: Oct 17, 2015 20:46 Messages: 25 Offline

Oct 23, 2015 17:41

Well, it handles them OK if I just output 'em at the lower frame rate, or in another format like MP4. Just seems odd it would whiff on them at native frame rate in WMV. I like using the WMVs because they seem to look pretty good and are a good deal smaller than the MP4s.

optodata

Senior Contributor Location: California, USA Joined: Sep 16, 2011 16:04 Messages: 8630 Offline

Oct 24, 2015 01:49

I agree that getting sample of the original clips would really help.

Can you tell if the silent section is "added" - as in the two parts should play back-to-back (like I assume the video does) or is there missing audio where the silence is now?

This message was edited 1 time. Last update was at Oct 24. 2015 01:49