Puzzling playback glitch

[terrypin]

I wasted an hour or two trying to isolate a problem with an MP4 that I'd exported from my video editor, before discovering that the problem was apparently down to MPC-HC and not my video editor (Magix Movie Edit Pro 2013 Premium).

The video plays perfectly in other players such as WMP, VLC, BS Player and KMPlayer. But in MPC-HC (latest version), my default player of choice, there is one very brief flawed section.

I've rendered 14 seconds of my project which shows this glitch at around the 10 s point. Here's that 46 MB file:

https://dl.dropboxusercontent.com/u/4019461/MPC-HC-Puzzle.mp4

Can any of the experts suggest what might be happening here please? I changed my MP4 association on this XP PC some months ago from VLC to MPC-HC and would be reluctant to reverse that as overall I'm happier with MPC-HC. But during an editing project I don't really want to have to re-check all my exports in two players.

--
Terry, East Grinstead, UK

[mike20021969]

I watched it a few times. I see no glitches at all using Windows Media Player. All I see is cross fading maps.

[raffriff42]

No video glitch with MPC-HC AFAICT. What should we be looking for?

First crossfade looks pretty smooth, but second and third crossfades seem to update very slowly (12fps?)
Simply re-encoding with VirtualDub or ffmpeg fixed the problem.
Odd crossfades were not seen in VLC, but were seen in MPC, MPC-HC, PotPlayer and SMPlayer
(of course, since the fades were the only "movement," I could have been seeing extreme lag on playback)

Audio breaks up a bit - is that your issue? Seems to be permanently recorded - ffmpeg did not flag any errors.
Audio breaks up in all players; might be a little more severe in MPC-HC.

EDIT here is a chart of frame render times in MPC-HC, showing two large hiccups - enough to bring the average FPS down to 23.
https://www.dropbox.com/s/ovl4bahw7i5f8tl/mpc-hc-Puzzle%202013-08-22%2014-55-54-25-Time.png?raw=1

Here's VLC Player
https://www.dropbox.com/s/2rx48ikmgn75coc/vlc-Puzzle%202013-08-22%2015-01-19-20-Time.png?raw=1

Frametimes in media players have not been studied in depth AFAIK, and these charts may mean nothing.
However, since the audio breakup correlates with frame render time hiccups, it may be pointing to a real problem.
I have no idea what that problem might be.

[vivan]

I see decoding problem when using QuickSync decoder (and dxva too):
http://3.firepic.org/3/thumbs/2013-08/23/zg7l7xw6nz7z.png (http://3.firepic.org/3/images/2013-08/23/zg7l7xw6nz7z.png)

With software decoding everything is fine. So try disabling dxva H.264 decoder in mpc-hc (or get latest nightly (http://nightly.mpc-hc.org/) with LAV filters and select software decoder)

I think this a video stream problem, however software decoders seems to cope with it.

[terrypin]

No video glitch with MPC-HC AFAICT. What should we be looking for?

https://dl.dropboxusercontent.com/u/4019461/MPC-HC-Glitch-1.jpg

--------------------

@vivan
Thanks, just saw your reply as I was about to send this. Yes, that's the glitch. Will try your suggestion tomorrow.

--------------------

@mike20021969
As per my first post, WMP plays it OK, it's MPC-HC that's the problem.

--
Terry, East Grinstead, UK

[raffriff42]

https://dl.dropboxusercontent.com/u/4019461/MPC-HC-Glitch-1.jpgTake another look at your image. You were using the Overlay renderer in MPC-HC, weren't you? Your screen grab is black - or rather, the part of your screen grab showing a live Overlay renderer output is black. When you made your image annotations you were seeing the live MPC-HC overlay through a transparent window in your image. This is one reason not to use Overlay renderer at all if possible.

[terrypin]

Take another look at your image. You were using the Overlay renderer in MPC-HC, weren't you?... This is one reason not to use Overlay renderer at all if possible.

Oops! I could have sworn I viewed that screenshot before I posted but plainly not, sorry.

I've never changed the default settings. Just want to use the player in no-brainer mode, playing everything I ask it to.

How do I know whether I'm using 'Overlay renderer' or not? How to switch it off? I've tried File > View > Renderer Settings and see no mention of it. Neither Reset to default renderer settings nor Reset to optimum renderer settings removed the glitch.

Assuming you've now seen that, as illustrated by Vivan, can you step me through the detailed settings I need to fix it please?

@Vivan
"With software decoding everything is fine."
How do I implement that please?

"So try disabling dxva H.264 decoder in mpc-hc"
How?

--
Terry, East Grinstead, UK

[vivan]

You can select renderer here:
http://firepic.org/thumbs/2013-08/24/012pqfix35sm.png (http://firepic.org/images/2013-08/24/012pqfix35sm.png)
But switching renderer won't fix it, since such image corruption is decoder fault.

To disable DXVA (if you're using 1.6.8 or older MPC-HC) - choose Internal Filters tab and untick H264/AVC (DXVA) in the right column.
If you're using 1.7.0 (nightly), double click H264/AVC there and select None in "Hardware Decoder to use" list.

[terrypin]

You can select renderer here:
http://firepic.org/thumbs/2013-08/24/012pqfix35sm.png (http://firepic.org/images/2013-08/24/012pqfix35sm.png)

To disable DXVA (if you're using 1.6.8 or older MPC-HC) - choose Internal Filters tab and untick H264/AVC (DXVA) in the right column.

Thanks, but disabling DXVA didn't remove the glitch.

And madVR (whatever that is!) is 'unavailable'.

https://dl.dropboxusercontent.com/u/4019461/MPC-HC-Glitch-2.jpg

I arbitrarily tried 'Old renderer' but the brief glitch was still present.

--
Terry, East Grinstead, UK

[raffriff42]

> the problem was apparently down to MPC-HC and not my video editor (Magix Movie Edit Pro 2013 Premium).

At this point I don't think so. As Vivan noted above, the video stream seems to be bad at some point(s). Different applications (or renderers) have different methods of error concealment (https://www.google.com/search?q=error+concealment). The visible glitch you note is the renderer repeating the last valid row of macroblocks to the bottom of the frame (it looks that way anyway). The applications that don't show this are simply repeating the last good *frame* in its entirety. No glitch is seen, but motion stutter is seen instead, as I noted above: "of course, since the fades were the only "movement," I could have been seeing extreme lag on playback."

EDIT
Selecting Overlay on my end lets me see the glitch. I prefer the Haali renderer BTW; it's mature and works well.
Can't detect any errors with ffmpeg, VirtualDub, VLC or even Grau GbR HD Video Repair Utility (http://www.videohelp.com/tools/Video-Repair-Tool). That doesn't necessarily mean there aren't any errors, just that I can't detect them...
And again, re-encoding fixes the video problem, although the audio breakup remains. Tried simply remuxing; unfortunately it does not help.

[terrypin]

> the problem was apparently down to MPC-HC and not my video editor (Magix Movie Edit Pro 2013 Premium).

... I prefer the Haali renderer BTW; it's mature and works well.

Thanks - that fixed it for me!

I'll leave it set and see if it causes problems with other files.

--
Terry, East Grinstead, UK