A curious little puzzle with .mts file import in MEP2015

brucehusker wrote on 11/12/2014, 5:26 PM

Hi Gang...I record video with a Canon Vixia HF G20, which saves video as .mts files. I transfer these files to my computer via usb and edit and burn with MEP. I've recently begun using my copy of 2015 which now appears to work better after some bug fixes. I was editing some video of my grandson's football game a couple of days ago, and noticed that every .mts file appeared to have frozen frames at the end of each clip. The last good frame of the clip was the one frozen when I scrubbed by hand and it appeared as a black frame on the timeline. The number of black frames increased with each clip that was longer in duration. I actually had to scrub to the end of each clip and cut the offending portion out. This was tedious, so I tried loading the same clips into MEP 2014. No frozen or black frames appeared. I checked my program settings in 2014, and noticed that I had "automatically create frametable during import" checked. I was advised to do this a couple of years ago when I had audio sync problems. So I fired 2015 back up, checked my program settings, and saw that I had it checked there as well. So just for fun, I unchecked it and then reloaded all my files. Lo and behold, no frozen or black frames anywhere. And with it unchecked, I still had good audio sync. My OS is Win 8.1 64 bit. Any clue as to what is going on here

Regards...Bruce

Comments

Scenestealer wrote on 11/13/2014, 3:05 AM

Hi Bruce

No surprises there! I never have this checked nor do I perform it on .mts files after seeing similar behaviour. Magix support do not recommend it unless something is very odd with your footage and then do not try it on anything that has been edited already as this can create a real mess. This function was created way back to fix (sync.) problems with old Mpeg2 disc camcorder footage.

Peter

brucehusker wrote on 11/13/2014, 4:56 AM

Good to know...thanks!

Regards...Bruce

browj2 wrote on 11/13/2014, 1:31 PM

Hi,

Speaking of creating frame table, I have been importing into MEP old VHS files in MPEG format that I had imported onto the computer from the original VHS cassettes (that was heavy equipment to lug around compared to today). I noticed that when the file was over approximately 1.5GB, both MEP2015Premium and VPX6 created frame tables ("Building frame-table for quick MPEG addess...") when importing the file onto the timeline. The "Automatically create frametable during import" is unchecked in both programs. In the preview monitor in VPX6, "Reduce resolution" is checked.

In VPX6, I have checked "Automatically create waveform during import" but "Automatically create frametable..." is definitely not checked.

Any idea why the programs do this even with the box unchecked?

Can you replicate this?

As well, I noticed that in VPX6, the program always does a "Creating graphics data.." when I import, but MEP2015 does not always do this.

Any idea as to why this has to be done? Does it have to be done? If not, is there a way to turn it off?

Thanks,

johnebaker wrote on 11/13/2014, 1:57 PM

. . . . Any idea as to why this has to be done? Does it have to be done? If not, is there a way to turn it off? . . . .

Yes it does have to be done on large files, the video/ audio time synchronisation drifts, the larger the mpg file the bigger the drift.

You would not really want to turn this off because of the synchronisation drift can be several seconds on 30 - 60 min long mpg file.

When the program streams have been encoded they are often concatenated, ie made sequential, this causes the timing values for audio to be reset to zero such that they then begin incrementing again. When this occurs the frametables must be recreated to resync the audio to video.

John

Scenestealer wrote on 11/13/2014, 2:18 PM

Hi John

"I noticed that when the file was over approximately 1.5GB, both MEP2015Premium and VPX6 created frame tables ("Building frame-table for quick MPEG addess...") when importing the file onto the timeline."

I have not seen this behaviour since quite a few versions of MEP back but then I have not used MPEG2 much in recent years. I am not 64Bit yet so I can not test with 2015 or VPX but I think MPEG2 needs to do this at some point after import. Not sure why though.

The "creating graphics data" is the creating of the wave form graphic on the timeline and it is selectable in the Program settings (Audio Video tab) because it uses slightly more resources to display and update when previewing.

Peter

Scenestealer wrote on 11/13/2014, 2:55 PM

I would still not create a frametable automatically or manually for MPEG4 .mts import. It seems that MPEG2 will still automatically recreate a new frametable if needed, even with the program setting unchecked.

John CB - I presumed your last question was reffering to the graphics data?

Peter

browj2 wrote on 11/13/2014, 7:42 PM

Hi Peter and John,

Create graphics data: now I understand that this is for creating the waveform. I noticed that it was automatic in VPX6 (I have it turned on) and not in MEP2015, which explains why I didn't see it in MEP2015. And yes, Peter, my last question was about this.

Create frametable: understood. I will leave it unchecked and go with the default that creates it with large mpeg files. That way it shouldn't do it with mts, which is what I use mostly.

I did have a desync between audio and video for a part near the end of one of the large mpeg files. It was quite obvious as my wife was singing and the audio was out by almost a second. It seemed to just start towards the end of the file. The VHS video was copied from the master of the community TV station which (that, who? aaah, English grammar) filmed the event, I believe. I will take a closer look at the others parts and files to see if this happens often. I didn't notice it in other parts of this particular file or other VHS videos so it may be just an anomaly. With VPX6, I can adjust the audio to finer than a frame, a capability which I quite like.

Thank you both for your replies. This cleared up a couple of annoyances that I can live with now that I understand what is happening.

terrypin wrote on 11/14/2014, 1:53 AM

"The VHS video was copied from the master of the community TV station which (that, who? aaah, English grammar) filmed the event, I believe."

Hi John,

That always gives me pause for doubt too! I found this link that reveals all:

http://www.grammarbook.com/grammar/whoVwhVt.asp

BTW, never heard any more from you here:
http://www.magix.info/uk/mep-2014-selection-puzzle.forum.1111464.html

Did my couple of posts help?

browj2 wrote on 11/14/2014, 12:07 PM

Hi Terry,

I answered the other thread and gave additional detail, just to confuse the issue even more.

Thanks for the grammar link. This is more efficient than looking through the grammar book somewhere on my bookshelf. I will still probably struggle with these, but the explanation of essential and non-essential phrases certainly helped my comprehension.

Regards,