EDEN BETA 3: Refresh Rate No Longer Changing

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dclindner Offline
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Post: #1
Since migrating from EDEN BETA 2 to BETA 3 the refresh rate no longer changes to match the movie fps. It seems to remain at 60fps no matter what the movie.

For example, in the debug log included, "Picture Perfect" reports 30fps for the opening and then reports to 23.95 as the movie starts. Refresh remains at 60 during the entire movie.

I've tried defining <measurerefresh> in advancedsettings, but it didn't change the symptoms.

http://pastebin.com/ns0VFQma

I've seen this on several movies and several tv episodes. "sync to display" is enabled.

This worked fine in Eden BETA 2.

Any thoughts?

Thanks,
Doug
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bobo1on1 Offline
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Post: #2
Adjust refreshrate is working fine, the problem is you're playing an NTSC dvd which is reported as 59.94 fps, in the past XBMC would detect 23.976 fps video on an NTSC dvd by checking the video timestamps, but this was disabled because it caused too many problems.
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dclindner Offline
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Post: #3
bobo1on1 Wrote:Adjust refreshrate is working fine, the problem is you're playing an NTSC dvd which is reported as 59.94 fps, in the past XBMC would detect 23.976 fps video on an NTSC dvd by checking the video timestamps, but this was disabled because it caused too many problems.

That's interesting bobo1on1. Thanks for checking.

I can't say I completely understand it, though. I haven't noticed significant judder like I used to see when the refresh rate wasn't adjusted accordingly. I do notice some, though. Is this the trade-off, should I now expect some judder as a result, or am I still missing something?

BTW, is there a particular pull or trac request I could review that describes why this change was made?

Thanks,
Doug
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dclindner Offline
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Post: #4
While I can't judge why this change was induced for BETA 3, I am not entirely sure I'm now seeing the best results, certainly not comparable to what I "thought" I saw before.

Occasional judder is once again noticeable to me and now I don't seem to have a way of adjusting the display to compensate.

I think I now understand the NTSC comments, though.

Something is odd, here. Is anyone else experiencing a similar challenge?

Thanks,
Doug
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dclindner Offline
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Post: #5
Interesting statement made in the 24P Wiki.

http://en.wikipedia.org/wiki/24p

Quote:24p on DVD

DVDs, however, are capable of storing the native 24p frames. Every Hollywood movie is laid to disc as a 24p (actually 23.976p – see below) stream. With a progressive-scan DVD player and a progressive display, such as an HDTV, only the progressive frames are displayed and there is no conversion to an interlaced format – eliminating the appearance of any interlace or de-interlacing artifacts. When displayed on a standard NTSC TV (which only displays 60i) the DVD player will add 3:2 pulldown to the signal.

In traditional television broadcast and VHS, the video stream has 3:2 pulldown added. This material cannot be displayed progressively without the resolution loss of de-interlacing, unless the de-interlacer has accurate cadence detection.

If this is indeed the case, it would give a reasonable explanation to the problems potentially being experienced.

When I check MediaInfo for the original movie I reported above (Picture Perfect), it reports the following:

[INDENT]Video
ID : 224 (0xE0)
Format : MPEG Video
Format version : Version 2
Duration : 1h 41mn
Bit rate mode : Variable
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate : 29.970 fps
Standard : NTSC
Compression mode : Lossy [/INDENT]

It's showing 29.970, not 59.94, although I'm not sure this really matters entirely.

I'm continuing to flog this issue because I'm not entirely satisfied with the quality of the video playback in BETA 3. BETA 2 produced much more pleasing playback, for the most part (at least to me). Judder has crept back into the playback, or so it seems to me, and I would like to have the option of turning this back on. I am assuming "this" means that XBMC uses the timestamps of the encoded video to determine the fps instead of what the file reports.
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bobo1on1 Offline
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Post: #6
The problem is if you have a dvd that switches between 23.976 fps and 59.94 fps, the fps calculation completely ruins the playback.
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dclindner Offline
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Post: #7
Quote:The problem is if you have a dvd that switches between 23.976 fps and 59.94 fps, the fps calculation completely ruins the playback.

Thanks, again, bobo1on1.

I have never seen such a condition. I have over 500 DVDs in my library and most all will shift to 24fps (under BETA 2) after a few seconds of playing. They used to remain at this fps and I've not seen a condition where it shifted back and forth. There are a few intros that have played at higher fps, but the main movie always was at 24fps.

All I can say is that playback in BETA 3 does not seem as good as it was in BETA 2 for these particular sources. I watched about 10 movies over the weekend and all exhibited some form of judder.

For BD sources, they shift to 24fps right away and play well throughout.

You guys can make the call, but I presently don't see a positive benefit to the change that was made between BETA 2 and BETA 3. I must be distracted.
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bobo1on1 Offline
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Post: #8
https://github.com/xbmc/xbmc/commit/d73a...d43cc99795

You can now enable it again by putting this in advancedsettings.xml:
Code:
<advancedsettings>
  <video>
    <fpsdetect>2</fpsdetect>
  </video>
</advancedsettings>
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dclindner Offline
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Post: #9
That's incredible, bobo1on1.

Thank you!

I'm very happy to have an option.

I'll await the change to make it's way into release.
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bigbully Offline
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Post: #10
+1 thanks for the option. I also recently discovered a couple of movies transcoded from DVD that won't switch framerates anymore.
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dclindner Offline
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Post: #11
I was watching another movie last night and noticed significant judder. This got me thinking.

The fps was 31.97 and of course the refresh rate was 60. I then deleted the measurerefresh from the advancedsettings and tried again. The fps was reported at 23.97. Hmmm. Also, the judder was pretty much gone. The refresh rate stayed at 60.

Does this make any sense at all?

I was then wondering why there might be a correlation between fps and judder. It used to be that if the refresh rate didn't match the fps, there was judder. Now it seems if the fps doesn't match the pre-telecine rate there is judder. Is ffmpeg doing something different when the fps changes?

I was wondering if ffmpeg removes the duplicate frames when the fps is 24 and re-executes a 3:2 pulldown to match the refresh rate. Are these duplicate frames that are encoded in an NTSC DVD to bring it to 29.97 once removed the missed frames that are counted when the refresh rate of 24 matches the fps detected?

This may be a silly notion, but the seems to be a correlation between fps and refresh rate and the presence of judder that goes beyond just matching the refresh rate. Further, is there a correlation between fps and missed frames? Is ffmpeg removing duplicate frames and considering this a miss?

If I'm off base so be it, but I thought the observation interesting.
(This post was last modified: 2012-02-15 22:58 by dclindner.)
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bobo1on1 Offline
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Post: #12
Never use <measurerefreshrate> in advancedsettings.xml unless the detected refreshrate in the codec info is wrong, the refreshrate measurement isn't very reliable, and doesn't bring any improvement at all, except when windows returns the wrong refreshrate for your monitor.
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bigbully Offline
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Post: #13
bobo1on1 Wrote:https://github.com/xbmc/xbmc/commit/d73a...d43cc99795

You can now enable it again by putting this in advancedsettings.xml:
Code:
<advancedsettings>
  <video>
    <fpsdetect>2</fpsdetect>
  </video>
</advancedsettings>

I added this to advancedsettings and the refresh now seems to be working again with the new RC1 update. I've only tested a couple of movies that weren't working, so I'll keep an eye out, but thanks for this in the meantime.
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craigdabbs Offline
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Post: #14
sorry to bump a old thread but this closely matches a issue i have.

Im running Arch Linux with my XBMC machines which has now updated to the latest eden releases. With dharma my older TV's which supported 50hz and 60hz, used to playback 24p content at 50hz which makes sence as its the closest match to 24hz.

Sinch changing to eden however it plays all my 24p content at 60hz which introduces a little stutter (not much i admit). I have applied the settings posted above and looked at the xbmc log which is this

Code:
20:33:27 T:2886712128   DEBUG: Resolution default: 1280x720 @ 50.00Hz (14) not a very good match for fps 23.976 (weight: 0.043), trying 2:3 cadence
20:33:27 T:2886712128  NOTICE: Display resolution ADJUST : 1280x720 @ 60.00 - Full Screen (12) (weight: 0.001)

Anyway of changing that to play at 50hz Smile,

I can force it to play at 50 by using
<override>
<fpsmin>23.96</fpsmin>
<fpsmax>24.01</fpsmax>
<refresh>50</refresh>
</override>

but some of my mahcines move from tv to tv which some do support 24p.

Hope ive explained myself enough and hope someone can help.

Thanks
Craig Dabbs
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gpborges Offline
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Video  RE: EDEN BETA 3: Refresh Rate No Longer Changing
Post: #15
Hi folks, I'm struggling a LOG with DVD disc playback (NTSC DVDs) and with DVD ISO playback too, but just for some ISOs.

My system is built on top Ubuntu 12.04 LTS (minimal/server install) + XBMC Eden (from oficial repo). My HTPC has a Zotac IONITX-L-E board (NVIDIA ION - MCP79 Board) hooked to a Pana 42" Plasma TV + Onkyo Receiver NR-609. I have a pretty smooth playback for almost all my movies and it's switching to 23.97 accordingly.

After read various threads related to DVD / ISO stuttering and after performing various tests/debugs myself, I can also confirm that there is a very tight relation between the fps and refresh rate. I have the Indiana Jones collection as DVD ISOs and all 4 of them are very choppy. I took some screenshots to highlight when the playback stutters, as this one with a weird fps as 45.98 and refresh rate 59.94:

[Image: screenshot003.png]

Here another one with fps at 45.77 and refresh rate at 59.94:

[Image: screenshot007.png]

One more (movie scene) at 47.52 and refresh rate at 59.94

[Image: screenshot009.png]

And here, another DVD iso which plays flawlessly. Notice that here the fps is 59.94 and refresh rate is 29.97

[Image: screenshot014.png]

And last but not least... a Bluray ISO playback, really smooth... fps and refresh rate both at 23.97 (that's why it's so smooth...)

[Image: screenshot031.png]

In summary, I always see stutter when the refresh rate doesn't match the fps for any reason. When it does, everything runs smoothly.

I will try the advanced setting:

Code:
<advancedsettings>
  <video>
    <fpsdetect>2</fpsdetect>
  </video>
</advancedsettings>

And will get back here with the results.

If anyone wants too see my debug logs, they're in another threads:

Linux Choppy playback / Video stutter with Eden
http://forum.xbmc.org/showthread.php?tid=131393

[LINUX] Iso/DVD files playback issues
http://forum.xbmc.org/showthread.php?tid=117828

Linux XBMCBuntu/Eden - DVD playback speed
http://forum.xbmc.org/showthread.php?tid...pid1141350

Hope we get this sorted out!!!

Thx!
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