Xmedia Recode & Variable Frame Rate

[BazzaG]

Hi,

I've been using Xmedia Recode to convert my DVD & TV rips into MKV's using the x264 codec.

99.9% of my DVD's & TV rips are in PAL format at 25fps, TFF interlaced, anamorphic, etc.

For DVD's I currently use DVDFab to rip to a vob & then use VideoReDo QuickStream Fix to make sure the vob/mpg has been ripped OK.

I'm very much a newbie at video conversion & after trying several different tools I found the Xmedia Recode seems to suit me best. Having said that there are still some aspects of the pgm I don't like.

Anyway, I have noticed that XR almost always creates MKV's with: Frame Rate Mode = Variable (according to MediaInfo). I'm not knowingly doing so.

I've tried contacting the developer with no success.

All of the DVD's & TV rips that I have converted so far, have no audio sync issues or anything like that. Daum Potplayer has no problems playing the MKV's & I also have no issues casting the MKV's to my TV via Videostream.

However, I have read here & elsewhere the variable frame rate should be avoided.

On the "Video" tab XR has a option for Framerate, which by default is: "Keep Original". I have also set this to 25 but that doesn't make any difference.

Almost all of the various x264 video options are set to the default values & I can't see any other option that could be causing this.

For clarity this is the Video Info section from MediaInfo for a converted file:

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 8 frames
Codec ID : V_MPEG4/ISO/AVC
Bit rate : 3 297 Kbps
Width : 720 pixels
Height : 576 pixels
Display aspect ratio : 16:9
Frame rate mode : Variable
Standard : PAL
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Writing library : x264 core 148 r2538
Encoding settings : cabac=1 / ref=8 / deblock=1:0:0 / analyse=0x3:0x133 / me=umh / subme=9 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=5 / b_pyramid=0 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=0 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=20.0 / qcomp=0.60 / qpmin=10 / qpmax=69 / qpstep=4 / vbv_maxrate=10000 / vbv_bufsize=24000 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=3:1.00
Language : English
Default : Yes
Forced : No
Color range : Limited

I'm happy to continue to use XR, however, I'm concerned that I may have problems playing these videos in the future, perhaps a updated release of Kodi or whatever.

Is variable Framerate really a issue here & if so, should I start looking at other video converters out there?

Thanks
BazzaG...

PS. If there are any x264 encoding settings that you think I should change ... please let me know.

[poisondeathray]

In x264

--force-cfr

For ffmpeg libx264 (xmedia recode uses ffmpeg, IRC, I think you can enter custom commandline args in one of the profiles)

-x264opts force-cfr=1

[BazzaG]

Thanks for replying poisondeathray, however, I cannot see any option in XR to add my own additional options; at least not in the GUI.

The profile that I'm using is "Custom", I've tried looking for a 'custom.xxx' in any of the XR directories or anything that has a generic name.

I do have a option to save the settings to a file: "settings.xmr", perhaps I can add "force-cfr=1" to this file & then load it back into XR ... not really hopeful that will work though.

When I look at this file in the [h264] section all I see are the options that can be specified via the GUI, for example:

[H264]
Level=11
Profile=2
Tune=0
Preset=7
Framerate=0
DisplayMode=0

and so on.

If in the GUI I change Framerate: Keep Original to Framerate: 25, then save the settings, the above Framerate parm becomes:

Framerate=11

11 corresponds to where '25' is in the list of selectable framerates list as shown in the GUI.

Cheers
BazzaG...

[poisondeathray]

Not sure - the author changed the standard syntax for ffmpeg . There might be a way to hack the ini or config file. Or might be easier to use something else.

VFR is an issue for very few devices, but many editing software. If you're not going to be editing it (you shouldn't, you should rip the original DVD and edit that, not the re-encoded version), I wouldn't worry about VFR.

Another option - You can sometimes remux it and force a CFR framerate - if it really was a CFR source and nothing was decimated

[BazzaG]

I tried loading a modified settings.xmr file & as suspected it didn't work.

It would be very, very unlikely that I would edit the converted MKV file. The only files that I do edit in VRD are my TV rips to remove any excess at the start/end plus any ads, save as mpg & then convert.

(I'm aware that VRD can convert/save to MKV/H264 but I get better results from Xmedia Recode.)

On my old PC I previously used XviD4PSP v5.x which I liked a lot but that PC simply didn't have enough grunt to encode to H264 only to XVID AVI.

I do have XviD4PSP v7.x installed but I don't really like it much. I find it a little confusing, but it does output fixed framerate.

If I used XviD4PSP instead I would *REALLY* miss the Xmedia Recode option of adding auto-chapters, ie. a chapter every 5 mins, 10 mins or whatever. XviD4PSP v7 doesn't have a auto-chapter option & so far I haven't really worked out a quick way of manually doing so.

I've just noticed that on the XviD4PSP software page here there is a recent (April 2015) release of v5, maybe I'll give that a go.

Of course that's AviSynth based which may give me more de-interlace options than I have with Xmedia Recode or with XviD4PSP v7 .... I've had a couple of DVD's & 1 TV Rip that I've had real trouble getting decent looking de-interlaced video using any of the de-interlace options in XR, so in the end I left 'em interlaced.

Thanks muchly for your help
BazzaG...

[hello_hello]

One way to test if the video is variable frame rate.....

Open one of the MKVs with MKVMergeGUI. In the appropriate section (the GUI has changed and I'm still using the old version so I can't tell you exactly where) specify a frame rate (ie 25fps). Remux that as a new MKV. When you specify a frame rate using MKVMergeGUI it outputs a constant frame rate.

Open the original MKV with gMKVExtractGUI. Select the video track. Down the bottom, select "timecodes" as the extraction mode and extract. Repeat the process for the new MKV. You can then compare the two timecodes files. Do they seem any different? For a constant 25fps frame rate, the timecodes should be a nice and consistent 40ms apart. Like this:

# timecode format v2
0
40
80
120
160
200
240
280
320
360

[BazzaG]

Hi Hello_Hello,

I have v8.1.0 64bit of MKVToolNix installed but I couldn't find any framerate option in either MKVMergeGUI or MKVToolNixGUI.

Even so, I did try to remux a MKV but according to MediaInfo it's still variable.

-----

I installed gMKVExtractGUI v1.6.2.0 & extracted the timecodes, this is the 1st few lines:

# timecode format v2
0
45
85
125
165

The only 'odd' difference was 45ms between the 1st 2 timecodes. Thereafter, every other timecode was +40ms.

I looked at several other MKV's created by XMedia Recode & they were all similar, eg:

# timecode format v2
0
50
90
130

In each case the 1st time difference was >40ms & the remainder were +40ms.

So I'm guessing this is why MediaInfo shows framerate=variable.

TBH, I have no idea why. I presume that it's probably a minor bug in Xmedia Recode.

Cheers
BazzaG...

[hello_hello]

MediaInfo sometimes shows VFR for Handbrake encodes that are constant frame rate. I can't remember why exactly. Something about the time base used for the frame rate and any rounding of frame durations that might be required. I think. Maybe.... Don't quote me.....

I've no idea why there's an extra 5ms/10ms duration for the first frame, but I'd imaging it's nothing to stress about. It might be something to do with any audio delay being required (if the original DVD audio used one) and if it's a negative delay an appropriate amount will be removed from the beginning of the audio stream, and maybe, if an exact amount to match the delay can't be removed, there's a bit of fiddling going on to make up the difference. I think normally (and I'm just making up numbers as an example) if the audio delay is -120ms and the closest amount that can be removed is 130ms, it'll be removed and an audio delay of 10ms will be written to make up the difference. Maybe, instead of an audio delay, there's some fiddling with the first frame duration happening instead. That's just an idea. A theory. It's probably complete bullocks. And thinking about it, if it was making up for an audio delay, the frame duration would need to be less, not more. Oh well. It was a thought.....

Here's where you change the frame rate using the old MKVMergeGUI. I don't know how different the new version is.

[BazzaG]

Hi,

With regards to MKVMergeGUI ... to coin the phrase: I'm "blind as bat" (in reality a very poor phrase since bats aren't blind & have similar eyesight to us!!!).

Re-muxing a MKV file in MKVMerge with FPS:25 specified does the trick. But, as you say, it's probably nothing really to worry about anyway.

Cheers
BazzaG...