Output video seems to introduce Variable Framerate (which causes problems with other editors).

Glass

New member
So, I record various TV programs using my DVB-T2 receiver in .ts format. These original videos AFAIK have constant frame rate (25 fps - standard european broadcast framerate) or at least MediaInfo and programs like Premiere say so.
Then I remove unnecessary stuff with Videoredo and finally remux into .mp4 (a format supported by everything, including Premiere for possible further editing down the road).
Once I open pretty much any of those .mp4 videos with Premiere though, they appear choppy, frames are being repeated 2 anda 3 times and I get audio/video sync problems. Checking the sequence settings (set by the videos) or the video properties seem to reveal why is that but not what causes it: the reported framerate is a random number like 30.05 fps and a “variable framerate detected” apears. So do these new videos have VFR? I initially thought they don't, since MediaInfo doesn't report so. However, I am reading MediaInfo could report false negatives and after testing doing this it seems they have VFR indeed. I've also tried opening them with another video editor (Shotcut) and it reports VFR too so it i really doesn't seem like a Premiere quirk. So, what’s going on?
Does Videoredo change the (seemingly) CFR of the original ts. recordings into VFR for some reason? I've read several times in here that the program doesn't even support VFR, so I am pretty puzzled. Interestingly enough, If while trimming the videos I remux them into new .ts files (rather than .mp4) they play fine in Premiere and no VFR is being reported. Same goes if I drop the mp4 video back to Videoredo and remux back to .ts. Does anyone have any idea what's going on and how could I get mp4 videos without that problem? Without transcoding them of course, that would cancel the whole point of lossless trimming which is the point of using Videoredo in the first place. Thanks a lot.

Things I've tried:
  • Remuxing to mp4 before I trim stuff.
  • Quickstream fix.
  • Updating video card driver.
  • Updating Premiere and asking in several Premiere communities to make sure it's not a bug. As I've said the same thing happens if I open the mp4 video with another editor too anyway.
  • Using the latest Videoredo version.

Ryzen 3900x, Nvidia 1660 Super, 32 GB RAM, Windows 10 1909
 

musicvid

Member
Please post your MediaInfo properties for both input and output files. I should be able to tell you straightaway if it is CFR. VFR, or misreported.
No problem here, and I am doing shows weekly, btw.
 

Winnewup

Member
Hello,
are you sure with the framerate? E.g. in Germany broadcast via DVB-T2 uses 1080p/50 or 1080i/50 and the codec H.265. In most other countries the codec is H.264/MPEG-4 AVC, but in my opinion framerate is also p/50 or i/50.

Regards
Frank
 

Glass

New member
Hello,
are you sure with the framerate? E.g. in Germany broadcast via DVB-T2 uses 1080p/50 or 1080i/50 and the codec H.265. In most other countries the codec is H.264/MPEG-4 AVC, but in my opinion framerate is also p/50 or i/50.

Regards
Frank
Hi. I really do think our standard framerate is 25 FPS, at least I have never seen a local program recording .ts file with anything else. In any case, it shouldn't really matter since the output .mp4 files in question do not report any standard normalized framerates such as 29.97 (NTSC) or even 50 as you mention but seemingly random VFR such as 30.05 or 35.02 which doesn't make sense.

Please post your MediaInfo properties for both input and output files. I should be able to tell you straightaway if it is CFR. VFR, or misreported.
No problem here, and I am doing shows weekly, btw.
Thanks for your input. The Mediainfo sheets are as follows:

Original .ts recording:
General
ID : 106 (0x6A)
Complete name : F:\PVR\Unsorted\5-2\Sur09-02\New folder\(09022021_221848)001.ts
Format : MPEG-TS
File size : 359 MiB
Duration : 6 min 37 s
Overall bit rate mode : Variable
Overall bit rate : 7 579 kb/s

Video
ID : 2610 (0xA32)
Menu ID : 2600 (0xA28)
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4
Format settings : CABAC / 4 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 4 frames
Codec ID : 27
Duration : 6 min 36 s
Bit rate mode : Variable
Bit rate : 7 011 kb/s
Maximum bit rate : 18.0 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 25.000 FPS
Standard : Component
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : MBAFF
Scan type, store method : Separated fields
Scan order : Top Field First
Bits/(Pixel*Frame) : 0.135
Stream size : 331 MiB (92%)
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

Audio
ID : 2611 (0xA33)
Menu ID : 2600 (0xA28)
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 2
Codec ID : 3
Duration : 6 min 37 s
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Sampling rate : 48.0 kHz
Frame rate : 41.667 FPS (1152 SPF)
Compression mode : Lossy
Delay relative to video : -1 s 51 ms
Stream size : 9.09 MiB (3%)
Language : English

Menu
ID : 7023 (0x1B6F)
Menu ID : 2600 (0xA28)
Duration : 6 min 37 s
List : 2610 (0xA32) (AVC) / 2611 (0xA33) (MPEG Audio, English) / 2613 (0xA35) (DVB Subtitle) / 2615 (0xA37) ()
Language : / English




Trimmed Output .mp4 file:
General
Complete name : F:\PVR\Unsorted\5-2\Sur09-02\New folder\(09022021_221848)001.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 40.0 MiB
Duration : 39 s 288 ms
Overall bit rate mode : Variable
Overall bit rate : 8 550 kb/s
Writing application : VideoReDo (Lavf58.29.100)

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4
Format settings : CABAC / 4 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 4 frames
Format settings, GOP : M=4, N=24
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 39 s 260 ms
Bit rate mode : Variable
Bit rate : 5 264 kb/s
Maximum bit rate : 18.0 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 25.000 FPS
Standard : Component
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : MBAFF
Scan type, store method : Separated fields
Scan order : Top Field First
Bits/(Pixel*Frame) : 0.102
Stream size : 39.1 MiB (98%)
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Menus : 3
Codec configuration box : avcC

Audio
ID : 2
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 2
Codec ID : mp4a-6B
Duration : 39 s 288 ms
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Sampling rate : 48.0 kHz
Compression mode : Lossy
Stream size : 921 KiB (2%)
Language : English
Default : Yes
Alternate group : 1
Menus : 3

Menu #1
ID : 3
Codec ID : txet
Duration : 39 s 280 ms
Language : English
Menu For : 1,2

Menu #2
00:00:00.000 : Chapter 1



Furthermore, I think it might be useful to check the following table I've made, trying different things with the same .ts recording. Hopefully someone makes something out of all this because I don't, I just don't get why I have problems with .mp4.


WINWORD_qtZVNhK2dc_cr.png
 

Dan203

Senior Developer
Staff member
Both of those files show 25fps. VideoReDo always outputs a static framerate. It's literally impossible for it to output variable frame rate, so if you see it reported as such then it's a false positive from MediaInfo.

That's not to say you don’t have an issue, just that it's not the framerate. There are other things, like repeat frames, that VideoReDo passes through that Premiere might not like. Unfortunately the only way to get rid of those is to do a full recode, rather than a smart edit.
 

Glass

New member
Unfortunately the only way to get rid of those is to do a full recode, rather than a smart edit.
Thanks for your reply Dan. As you can imagine, this pretty much cancels the whole point of using Videoredo in the first place. Meaning, without the benefits of a smart edit (lossless + fast), one could do a recode by using Premere only, from the start.
Is this expected behaviour with every .ts ----> .mp4 remux? I mean, I understand there might be no interest to get to the bottom of this or treat it as a bug (if it's a bug of course), and that's okay, but could you please at least help me understand what's going on, in order to seek assistance elsewhere? What "other things" could Videoredo pass through that Premiere (btw, as I've said it's not an issue manifested on Premiere only) doesn't like? And how come the problem doesn't occur if I remux into another .ts file instead of .mp4, or even if I drop the offending .mp4 back to Videoredo and remux anew (smart edit) to .ts? I mean, that alone tells me the recording itself should be fine and that there might be a way for Videoredo to prevent the problem from occuring on .mp4 files too (maybe via QSF, which at the moment doesn't help with this?).
 

Dan203

Senior Developer
Staff member
Actually that's a good way to test if it is actually being caused by repeat frames. Open the original in Premier. Does it have the same issue? If not then it's not repeat frames Causing the problem.

These videos aren't from a Tesla are they? Recently I grabbed a video from my Tesla and tried to edit it in VideoReDo and it had an effect similar to what you describe. After analyzing it we discovered it had an extra I frame inserted at every GOP. Premiere seemed to just ignore them on the original, but once processed with VideoReDo it caused a weird jump every second or so. This was something we'd never seen before so we're not quite sure how to fix it. We're still investigating.
 

Glass

New member
Actually that's a good way to test if it is actually being caused by repeat frames. Open the original in Premier. Does it have the same issue? If not then it's not repeat frames Causing the problem.
No it does not. It plays fine. The original .ts recording and the exact same snippet trimmed with Videoredo but outputted as .ts play absolutely fine on Premiere. No double-triple frames, no audio/video synch issues, no VFR reported in properties. Please check the table I've uploaded at the end of my second post for more info.

These videos aren't from a Tesla are they?
No they are not, I am not even sure what a Tesla is. They are from a DVB-T2 receiver. This one in particularly if that says anything:
Please notice that while it is supposed to support H.265/HEVC too, our broadcasts are still H.264 as you can see in the MediaInfo files so that's not the culprit. Would it help if I upload any samples?
 

musicvid

Member
I think the fact your broadcast stream is encoded MBAFF may have something to do with your observations.
Both files are 25fps constant frame rate.
 

Dan203

Senior Developer
Staff member
No it does not. It plays fine. The original .ts recording and the exact same snippet trimmed with Videoredo but outputted as .ts play absolutely fine on Premiere. No double-triple frames, no audio/video synch issues, no VFR reported in properties. Please check the table I've uploaded at the end of my second post for more info.


No they are not, I am not even sure what a Tesla is. They are from a DVB-T2 receiver. This one in particularly if that says anything:
Please notice that while it is supposed to support H.265/HEVC too, our broadcasts are still H.264 as you can see in the MediaInfo files so that's not the culprit. Would it help if I upload any samples?
Please send an email to support. We'll likely need to get a sample from you to figure out what's going on.

and FYI a Tesla is a car. :) It has built in cameras that are always recording and you can capture those recordings to an external drive and transfer them to a PC.
 

Glass

New member
I think the fact your broadcast stream is encoded MBAFF may have something to do with your observations.
Both files are 25fps constant frame rate.
I really don't know how MBAFF would or wouldn't be a factor, all I can point out is that the original recording is encoded MBAFF too, and that since I am looking for a solution in other places too, this is a remark someone made which might or might not be related with what you are saying:
I do not see the info for the ts
It should say: "Scan type, store method : Interleaved fields" for typical "interlace" or mbaff , but yours' says "separated fields."
That suggests double the framerate, as the field rate... when you separate fields for 25fps interlaced you get 50fps indvidual fields.


Please send an email to support. We'll likely need to get a sample from you to figure out what's going on.
Will do. I've also put together a list with improvement suggestions / feature requests I mean to send for a while, I can send that too if there's interest. Any ideas whether MBAFF might have to do anything with the issue as musicvid suggests?

and FYI a Tesla is a car. :) It has built in cameras that are always recording and you can capture those recordings to an external drive and transfer them to a PC.
Oh I thought it's an DVB-T2 receiver. A bit Black Mirroresque, don't you think?!
 
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