Stutter playing 50fps on TV

[akkers]

I shot some footage on a action cam at 50fps progressive. I edited it in 50p as well on Premiere and output it in MP4 at 50p 20mb/s.

However, when I play this MP4 file on a LED PAL tv the picture tends to stutter a little (especially on pans and movement).

I would expect 50p footage to be rock solid but it stutters and is far worse than interlaced.

[Bernix]

Hi,
there can be various reason for this. How you have video connected to TV? USB stick or external HDD or cd/dvd/bluray? Probably speed of transfer video can be problem.
Also but it is less probably check your tv specification, what codecs it supports and what level and so on.
And you also can post Mediainfo in text form of the problematic file. And mentioned USB stick and TV name.
Edit: Don't forgot, that peak of transfer can be different from average bitrate. If you didn't use constant bitrate.

Bernix

[akkers]

Its a Sony Bravia KDL55W8 LED HD 1080p TV and I normally play interlaced/Progressive MP4 files without much problem through a USB stick.

General
Complete name : H:\Yi4K\Out\Part2.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (mp42/mp41)
File size : 4.94 GiB
Duration : 33 min 51 s
Overall bit rate mode : Variable
Overall bit rate : 20.9 Mb/s
Encoded date : UTC 2017-12-23 18:41:56
Tagged date : UTC 2017-12-23 18:46:13
©TIM : 00:00:00:00
©TSC : 50
©TSZ : 1

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L4.2
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Format settings, GOP : M=4, N=50
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 33 min 51 s
Bit rate : 20.5 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 50.000 FPS
Standard : PAL
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.198
Stream size : 4.86 GiB (98%)
Language : English
Encoded date : UTC 2017-12-23 18:41:56
Tagged date : UTC 2017-12-23 18:41:56
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 33 min 51 s
Source duration : 33 min 51 s
Bit rate mode : Variable
Bit rate : 317 kb/s
Maximum bit rate : 409 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 spf)
Compression mode : Lossy
Stream size : 76.9 MiB (2%)
Source stream size : 76.9 MiB (2%)
Language : English
Encoded date : UTC 2017-12-23 18:41:56
Tagged date : UTC 2017-12-23 18:41:56

[Bernix]

Here I started https://www.sony.co.uk/electronics/support/televisions-projectors-lcd-tvs/kdl-55w829b#manuals
From here https://www.sony.co.uk/electronics/support/res/manuals/Z012/Z012721111.PDF
I got here http://pdf.crse.com/manuals/14HE468112/EN/codeclist.html#10

And it seems 4.2 is high if I'm not wrong. Just check last link. But I think it should refuse this file and don't try to plays it.

Bernix

[jagabo]

The TV doesn't appear to support 1920x1080 at 50p. Convert to 1920x1080 25i or 25p. Or reduce the frame size to 1280x720 and encode at 50p.

[akkers]

No, it plays it ok (except that it stutters).

I have also output the footage to MPEG2 format (25p) and made a DVD. Unfortunately the DVD is also the same (shows stutter on pan and movement).

[Bernix]

I suppose dvd in 720x576x25
The media info you posted there is level 4.2 If DVD has same level, this can be source of your problems. It supports Mpeg1, TS and PS. And have you played DVD through DVD player of stored on USB? Because DVD player can have different limitation. And Mpeg2PS doesn't support aac, which is obvious.

[Attachment 44155 - Click to enlarge]

[davexnet]

Well if you created a DVD from 50P footage, the video was probably decimated 2:1 to create the 25p. This should not
cause stuttering, but will result in less fluidity, this should be expected. Perhaps something is wrong with the source file.

Play the DVD on the computer. If it looks good there, your TV, DVD player or source file could be at fault.

If you're still not convinced provide 10 - 15 seconds of the source video showing the problem

[akkers]

Thanks. I am starting to agree with you that maybe the source is dodgy. Unfortunately, I cannot play any of the source files directly on TV as the birate is too high and tv struggles. The files do play on teh computer but I am not sure about the quality; I thought it was my graphic card.

Anyway I am attaching a short clip and also uploading to YT.
https://youtu.be/YwN84pznKHY

[davexnet]

I played it on my US (NTSC) TV via the "cast to" mechanism in Windows 10. Despite the high bitrate and wifi connection,
it played pretty well. I looked at it frame by frame in Virtualdub; you can see an occasional up/down small jump in the video, not sure what
that is unless it is camera shake.
When I play it on my computer monitor there is something that detracts but it might be a clash with the monitor refresh rate (not sure).
Wait and see if anybody else chimes in, might get some other idea's.

[jagabo]

Try these.

[akkers]

Although the TV cannot play these latest settings out of the box, I believe it has been updated several times; its setup to automatically update via broadband. So that would explain that.

I will try the above files that jagabo has uploaded and report back.

[akkers]

Since I output the footage in 25p mpeg2 and made a DVD, it looks awful; the stutter is more pronounced.

Whats the best way to create a mpeg2 file? Should I output as 25i mpeg2 file and then make dvd?

[jagabo]

25p DVD will give you better resolution but less smooth motion. 25i will give you smoother motion but lower resolution. I recommend you post some samples of your DVD conversion. Some editors have problems with some videos and aren't frame accurate. They may skip some frames, repeat others, resulting in jerky motion.

How did the videos I uploaded play on the TV?

Also, 25p with no motion blur is going to flicker a lot with high contrast video. And all those thin lines in your video are going to flicker when downscaling unless you blur the source significantly.

[akkers]

Jagabo. The 25p file plays the worst on t.v. with white a bit of stuttering. The 1080/50 is stable but still there is a hint of stuttering.
The 720p file plays the better but it's not perfect.

I am beginning to think that there may be issues with camera or card.

[flashandpan007]

I am beginning to think that there may be issues with camera or card.

The files are fine, so the cam is fine, too. The camera is only shaking a bit -> no image stabilizer.
Just try to put the cam on a tripod a do a smooth pan test.

More likely to be a playing issue ...

[akkers]

Jagabo. The 25p file plays the worst on t.v. with white a bit of stuttering. The 1080/50 is stable but still there is a hint of stuttering.
The 720p file plays the better but it's not perfect.

I am beginning to think that there may be issues with camera or card.

[akkers]

The cam has built EIS which was turned on.

[flashandpan007]

try to put the cam on a tripod a do a smooth pan test

post a sample of it

[akkers]

Here are some files taken using a tripod. The first one is with original settings of EIS on, lens distortion on, Video quality High. Then I gradually turned all these off.

I think there is still some stutter.

[flashandpan007]

all files are fine, no stuttering, the little shaking, some videophiles could see is caused by the hands when turning the head of the tripod. Because of that "issue" there are very expnsive tripod heads available which do a better job for pros.
But are simple trick is also available:
https://www.youtube.com/watch?v=Fj6fMcJ18aA

So it is a playing issue. What refresh rate is the TV when playing the files?

[poisondeathray]

There might be playback issues, but there are source issue as well

There is a very tiny bit of vertical stutter in the source (I only looked at the first one) . There is a slight up/down motion on some frames, this was also evident in your first sample earlier . It's unclear if it's from bad tripod, bad hands, or bad camera. Go frame by frame around 750-754 and you will see this up/down effect

For horizontal panning, there is some minor "strobing".

Likely another thing that is probably contributing could be is compression issues, there might be some motion vector issues. There are aliasing issues that also contribute to this perception

If you go frame by frame , look at the tall vertical structure in the background you will see it flicker, even if you adjust the overbrights

[flashandpan007]

keep in mind it's a action cam

[poisondeathray]

keep in mind it's a action cam

Not all "action cams" are equal

I suspect this is a "cheapo" model , and all those little problems contribute to the perception of "stutter".

You get what you pay for

[jagabo]

Just on the off chance... does this play smoother for you?

[flashandpan007]

Just on the off chance... does this play smoother for you?

interesting file

[akkers]

The cam is Yi 4K model. It is a fairly reputable brand and has quite a following.

[flashandpan007]

Just on the off chance... does this play smoother for you?

@akkers: Do you like it better?

Yes, I know YI, if I remember correctly, they introduced the worlds first 4k60p actioncam. Not a crap brand
Nevertheless it is a actioncam. Do actioncams in general, or a specific model provide manual adjustments, like shutterspeed?
Shutterspeed is important for the look of pans.

[akkers]

No I don't think you can change shutter speed as I recall.
I previously had a gopro4 which produced rock solid 50p footage. Unfortunately I had to return that due to heating problems.

[flashandpan007]

What do you mean with "rock solid 50p footage"?