Author Topic: Bad frames at splice points when trimming AVCHD files  (Read 31939 times)
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« Reply #23 on: June 18, 2015, 05:19:19 PM »
... The marked  start frame of a selected fragment is always bang on, but 2-3 frames are now lost at the end of the fragment i.e. the end cut is made 2-3 frames before the marked frame.  So now, instead of overshooting by a full GOP (15 frames for 30PF), its undershooting.

It's been nearly six weeks now, and still no fix for what is a pretty fundamental flaw  :(

You can hardly say that Video Splitter "cuts and joins up video and audio streams perfectly" if it drops frames in the process.

Can't understand why resolving this would not be considered a priority, especially as you were already aware of this behavior:

We have already noticed such behaviour of Video Splitter.

I'd really like to use Video Splitter for native cut editing of AVCHD files, I really would, but frame accuracy is crucial for me.





 
« Last Edit: June 18, 2015, 05:26:43 PM by WorBry »

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« Reply #22 on: May 07, 2015, 04:47:47 AM »
Hello Olga,

Any developments?

Thanks.
Hello WorBry,

This issue is in our "to do" list at the present time.

As soon as there will be the updated version ready, I'll post here.

Thank you for your patience. 
Regards,
Olga Krovyakova
Solveig Multimedia

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Regards,
Olga Krovyakova
Solveig Multimedia

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« Reply #20 on: May 06, 2015, 08:53:53 AM »
Hello WorBry,

Thanks for your patience.

Please try to use Video Splitter 5 beta version with the fixed issue at the link below. Will it also work at your end?

http://solveigmm.com/files/SolveigMM_Video_Splitter_Home_Edition_5_0_1504_16_Beta.exe

http://solveigmm.com/files/SolveigMM_Video_Splitter_Business_Edition_5_0_1504_16_Beta.exe

Olga, What´s the link of newest Beta version?

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« Reply #19 on: May 05, 2015, 01:37:52 AM »
Hello Olga,

Any developments?

Thanks.

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« Reply #18 on: April 25, 2015, 12:28:27 AM »
Hello WorBry,

Thank you for your post. We have already noticed such behaviour of Video Splitter.
We will try to fix this in near future.
I'll write here as soon as the updated version will be released.

Thank you.
Regards,
Olga Krovyakova
Solveig Multimedia

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« Reply #17 on: April 24, 2015, 09:40:29 AM »
 
The last frame of each 'selected fragment' now respects the 'end' marker point, with no GOP overshoot - and that's in both frame-accurate and key-frame accurate modes.

Correction on that. The marked  start frame of a selected fragment is always bang on, but 2-3 frames are now lost at the end of the fragment i.e. the end cut is made 2-3 frames before the marked frame.  So now, instead of overshooting by a full GOP (15 frames for 30PF), its undershooting.

I picked it up when I was comparing the quality of the trimmed files and fragments with the source MTS files which I trancoded to a lossless YV12 intra-frame format (MagicYUV) to make reference clips cut at same frame points. For the metric quality tests (SSIM, PSNR) I also transcoded the Video Splitter outputs to MagicYUV. Couldn't understand at first why the frame lengths of the reference and test clips didn't match up, until I discovered that end frames were being deleted by Video Splitter. 

As a case in point:

1. Took a native 1080/30PF mts clip - 8670 frames

2. Made 5 cut marker points at random with Video Splitter (in Frame Accurate mode), producing six fragments.

3.  Saved all six fragments as individual files. The frame counts of the fragments were, in order: 1623,1370,1656, 1394, 921, 1692 = Total 8656.

4. Rejoined the fragments with Join Manager. Frame count of recombined clip  was 8656 - same as the sum of the saved fragments.  And when the clip was played back you could see a frame jump at the join points.

5. Then I used the same cut marker points to produce a trimmed file, excising the 1st, 3rd and 5th segments. Frame count of rendered trimmed file - 4456, which is the same as the sum of saved fragments 2, 4 and 6.

So, irrespective of whether the clip was trimmed or split into fragments, 14 frames were 'lost' with the 5 cuts. 

Something to be looked at I think.

Edit: I wonder, is this the reason why other 'smart trimmers' I've looked at (Video Cutter, Smart Render 4) perform more extensive GOP re-construction on both sides of a cut/re-splice point. In the case of Smart Renderer 4, that can often extend to five GOP's - that's 2.5 seconds of re-encoded video which is quite significant if you are editing relatively short clips. Please don't go that route if you can avoid it.  It's one of the reasons why I stopped using SR4 for cut editing AVCHD - that and the often low quality (low bit size) of the re-encoded frames. Same goes for Smart Cutter, which I only tried out.

Edit2: Just tested some 1080/60i MTS clips from my Canon HF-G10 and some 1080/60p MTS clips from a Panasonic TM700 and all show the same thing on splitting or trimming - deletion of 2-3 frames at the end of a selected fragment. So again, it's not some 30PF quirk.     







 
« Last Edit: April 24, 2015, 03:19:00 PM by WorBry »

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« Reply #16 on: April 23, 2015, 05:37:23 PM »
OK, thanks.

Thinking about it more, highlighting the Key Frames in some way (colored border or something) on the frame level (Frame Mode) timeline probably would be the better option - and probably the easiest to implement?

Cheers. 

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« Reply #15 on: April 22, 2015, 11:07:06 PM »
Hello WorBry,

Thank you for your suggestions.

We will discuss them with our tean and possibly add them to Video Splitter's next releases.

If such features appear in the product, I'll post here.
Regards,
Olga Krovyakova
Solveig Multimedia

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« Reply #14 on: April 22, 2015, 02:05:55 PM »
Thanks Olga.

Having just re-run some 'trimming' tests using the AVCHD sample clips I have to hand, the beta does indeed appear to have fixed the two issues I addressed.

The last frame of each 'selected fragment' now respects the 'end' marker point, with no GOP overshoot - and that's in both frame-accurate and key-frame accurate modes.

I also re-tested the 1080/30PF MTS clip I sent you that had produced the 'bad' (insanely low bit size) end B-frames on trimming. Although the re-encoded frames (as identified by the Elecard watermark) are, in general, slightly lower quality than the native frames when inspected closely (marginal loss of fine definition), that is, to some degree, only to be expected - but I could not see any 'bad' frames as such. And analyzing the trimmed streams with Stream Eye I couldn't see any frames with abnormally low (or null) bit sizes either.

Also, all of the trimmed AVCHD clips I've tested so far play back perfectly well on my PC (MPC-HC) and on a set-top player (PS3/HDTV)  - no skips, dithers or freeze-ups. 

I'll come back to you if I find any other issues on wider testing, but it's looking good. I think can see myself using Video Splitter for native cut editing of AVCHD clips.

If I might make a few suggestions/requests at this point:

1. Would it be possible to display in some way an analysis of those frames that will be (ideally) or have been re-encoded after rendering? In the trial version the re-encoded frames can be be recognized by the Elecard watermark. It would be helpful to have some means of identifying the re-encoded frames in the licensed version also. "Smart" native cut-editing is, after all, about preserving as much of the original source video as is possible.

2.  In the time-line 'zoom control' could you possibly include a 'Key-Frame' level view, in addition to frame level ('Frame Mode') ? I appreciate that at all zoom levels one can use the navigation controls to go to the next or previous key-frame, but I would find it useful to see a timeline displaying the key-frame thumbnails, at least for AVCHD files with a regular, repeating GOP structure. Or else maybe you could highlight the key frames in some way in the 'Frame Mode' view? 

Actually, what would be really nice is if there could be a 'scene change' view, or at least some way of marking on the time-line where scene changes occur. I am of course thinking of the type of feature offered in most NLE's where a clip placed on the storyboard timeline can be split at scene changes (as judged by scanned frame 'content'). Something for the future maybe? Still I'd settle for a 'Key-Frame Mode' view if that's readily do-able.

Thanks.

 
« Last Edit: April 22, 2015, 02:44:28 PM by WorBry »

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« Reply #13 on: April 21, 2015, 09:58:29 PM »
Hello WorBry,

Just for your knowledge, you can test it by clicking the "Later" button on the first window that will be opened after Video Splitter launching.

Thank you.
Regards,
Olga Krovyakova
Solveig Multimedia

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« Reply #12 on: April 18, 2015, 10:10:27 AM »
Hello Olga,

Well I'd like to test the beta but the 21 day trial evaluation period has now expired.

I have sent you an email.

Thanks.

« Last Edit: April 18, 2015, 10:33:27 AM by WorBry »

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« Reply #11 on: April 17, 2015, 11:06:52 PM »
Hello WorBry,

Thanks for your patience.

Please try to use Video Splitter 5 beta version with the fixed issue at the link below. Will it also work at your end?

http://solveigmm.com/files/SolveigMM_Video_Splitter_Home_Edition_5_0_1504_16_Beta.exe

http://solveigmm.com/files/SolveigMM_Video_Splitter_Business_Edition_5_0_1504_16_Beta.exe

Regards,
Olga Krovyakova
Solveig Multimedia

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« Reply #10 on: April 15, 2015, 11:48:32 PM »
I'm still here.

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« Reply #9 on: April 09, 2015, 07:37:27 PM »
Hello WorBry,

Thank you for files you have sent and excuse for the delayed answer.

We currently test them. As soon as there will be any results, I'll post here.
« Last Edit: April 09, 2015, 07:50:19 PM by Olga Krovyakova »
Regards,
Olga Krovyakova
Solveig Multimedia