Problems with choppy stuttering video

[helsing]

Hi!

I experience problems with video and audio that behaves "choppy" or "stuttering" in scenes with many fast moving details. For example if you look at BBC Planet Earth with scenes with fast moving flock of birds, bats or fish the video starts to "stutter" = meaning the picture freezes and every second it updates and acts as a kind of slide show with no audio.

I experience this problem for both
A) video 1838Kbps, 640*352 at 25fps in MPEG4(XviD) and audio 192Kbps, 48KHz, 2 channels, MP3
B) video 4819Kbps, 1440*1080 at 25fps in MPEG4(XviD) and audio 384Kbps, 48KHz, 6 channels, AC-3

I also experience this problem for
1) HomePlug network with myiHome server running on my PC.
2) plain old wired network (not wireless) with myiHome server running on my PC.
3) Putting the file directly onto USB memory stick and playing it from there will still result in choppy video, although not as often as in case 1 and 2 above. So this issue is not entirely network related.

Anyone else having had this problem. How did you solve it? Can you increase buffering somehow to improve matters?

Thanks

---

Clarification:
I don't have an internal HDD in my Popcorn Hour. (I had hoped I could deal without it :-)

[spawn]

must be something wrong with how these xvid encodes were done
naturally you should have no stuttering issue from an SD encode with 1838Kbps bitrate

I have a fullhd h264.mkv sample of the planet earth birdscene which spikes at 46mbps bitrate and playes fine through my network, and from my usb disc - no stuttering.

Could you post a mediainfo report ?

Which video output are you using ?

[helsing]

I am using 1080p 50Hz as video output on my Popcorn Hour.
(I chose 50Hz since the framerate is 25fps)

Mediainfo report:
General
Format : AVI
Format/Info : Audio Video Interleave
File size : 1.75 GiB
Duration : 48mn 8s
Overall bit rate : 5 204 Kbps

Video
Format : MPEG-4 Visual
Format profile : Streaming Video@L1
Format settings, BVOP : Yes
Format settings, QPel : No
Format settings, GMC : No warppoints
Format settings, Matrix : Default
Codec ID : XVID
Codec ID/Hint : XviD
Duration : 48mn 8s
Bit rate : 4 810 Kbps
Width : 1 440 pixels
Height : 1 080 pixels
Display aspect ratio : 4/3
Frame rate : 25.000 fps
Resolution : 24 bits
Colorimetry : 4:2:0
Scan type : Progressive
Bits/(Pixel*Frame) : 0.124
Stream size : 1.62 GiB (92%)
Writing library : XviD 1.1.0 (UTC 2005-11-22)

Audio
Format : AC-3
Format/Info : Audio Coding 3
Codec ID : 2000
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Surround: L R, LFE
Sampling rate : 48.0 KHz
Resolution : 16 bits
Stream size : 132 MiB (7%)
Alignment : Aligned on interleaves
Interleave, duration : 40 ms (1.00 video frame)

[spawn]

hmmm - could you try reindexing/remuxing with virtualdubmod - direct copy mode for both video and audio ?

[helsing]

I downloaded VirtualDubMod 1.5.10.2, opened the file I had problems with. I marked the beginning and end of the particular section I had problems with and chose "Save As..." in the File menu. In the pop-up I selected Video Mode = "Direct Stream Copy" before pressing Save. I did the same tests as described above with the new file that was created.

The results were exactly the same. I still had stuttering in the sequence also when viewing the file from USB memory stick... :-(

When I display the "Info" pane using the Popcorn Hour I can see that the bitrate peaks at 44+ Mbps before the stuttering begins and when the stuttering is in effect no bitrate is shown at all.

Any tips or tricks are welcome...

[steveh]

I've seen this issue on my homeplug (200AV) network, but as soon as I transferred the movies to the local hard drive it was fine (another point is that depending on how the bandwidth suffered, sometimes the latest firmware on the 110 wouldn't recover the sound, some kind of buffer filling issue but fairly reproducible).

Should note that the 200AV that the PCH was plugged into was hanging off an extension lead for testing, so not exactly the best environment for it! I'm fairly certain that when it's all where it should be it'll be fine.

[helsing]

Hmm, well yes thanks, but I experience this problem also when playing directly from a USB memory stick. No network is involved. (I don't have an internal HDD.)

[helsing]

Now I have also tested using a hi-speed SanDisk Cruzer Contour memory - which states it gives 25MB/sec reads.

Still the same problem with choppy stuttering video for this hi-bitrate video sequence.

This file plays fine on my PC (using VLC media player) so I don't think there is anything wrong with the file itself...

Any comments? Someone?

[chris57]

Why dont you upload the sample so we can view it?

[helsing]

(01-09-2009 10:26 AM)chris57 Wrote:  Why dont you upload the sample so we can view it?

Good idea. Where can I put it? (It's about 230MB)
Or should I put it on a tracker somewhere?

[helsing]

Ok, so I put it on 4shared.com.

Part 1
Part 2
Part 3

This is one file (222MB) which is splitted in three parts (since there is a size restriction). I splitted them using 7-zip (http://www.7-zip.org) and it's possible to merge them with that tool as well. Go to File - Combine files...

I really appreciate your help. I am most thankful! :-)

Cheers

[helsing]

Anybody had time to look into this?

Do anybody know of a diagnostic tool that somehow could analyze a video file and answer if it is sound and healthy (for the PCH)? Playing it on another device (PC, XBOX) isn't enough since there may be some fault tolerance in their software which isn't the case for PCH, right?

I mean whenever I get some choppy stuttering video I will always have to do some troubleshooting according to:
1) Is there anything wrong with the video file itself, wrong encoding, missing specifications, and what have you...?
2) There might be something wrong with the network. (I have requested a feature for checking network speed from the PCH)
3) It might be the case that this video won't be able to play on the PCH - either because of a bug, or simply because the PCH isn't able to playback that kind of content.

Currently I have not yet passed step 1. I.e. I really don't know if there is something wrong with the video file and if so is there anything I could do about it?

Any help is welcome... I am truly thankful for any help...

[spawn]

Yes - I have donwloaded your sample and tested it on my PCH

The file is fine except for 2 things

1. it has wrong aspect ratio flag 4:3 - should have been 16:9 - but thats just a side note unrelated to the stutter

2. the bitrate pattern is off the roof - this is the cause of the stutter you experience - allthough bitrate are reported by media info to be overall 10.8mbps - it spikes up to 50Mbps in the last scene at 2.20-2.22 were the fish stream fills up the screen with highmotion, and a couple other places it spikes to 33-46mbps. My setup are able to play the entire clip smooth except for 1-2 seconds around the 2.20 to 2.22 mark where bitrate spikes to 50mbps

Basically theres nothing wrong in your setup for getting stutter with this (or similar clips) - the file has just been encoded with to relaxed variable bitrate letting it spike above what is possible to play over network or even from usb stick or my internal laptop harddrive

[helsing]

Many thanks, Spawn. I am truly grateful for your help

(01-13-2009 10:15 PM)spawn Wrote:  1. it has wrong aspect ratio flag 4:3 - should have been 16:9 - but thats just a side note unrelated to the stutter

Another side note: Is this property something you could edit in the file? What tool would you recommend, if so?

(01-13-2009 10:15 PM)spawn Wrote:  2. the bitrate pattern is off the roof - this is the cause of the stutter you experience - allthough bitrate are reported by media info to be overall 10.8mbps - it spikes up to 50Mbps in the last scene at 2.20-2.22 were the fish stream fills up the screen with highmotion, and a couple other places it spikes to 33-46mbps.
My setup are able to play the entire clip smooth except for 1-2 seconds around the 2.20 to 2.22 mark where bitrate spikes to 50mbps

Basically theres nothing wrong in your setup for getting stutter with this (or similar clips) - the file has just been encoded with to relaxed variable bitrate letting it spike above what is possible to play over network or even from usb stick or my internal laptop harddrive

Ok. Would it be correct to say that the Popcorn isn't able to play sections with a variable bit rate of more than ~42Mbps?
Neither from network, USB or the internal hard drive?

When you are saying the clip is playing smooth (besides the 2.20-2.22 section) are you then playing from an internal hard drive or USB?
I don't have an internal hard drive so I am playing from a hi-speed USB stick and I am getting stutters at several of the peak sections,
not just the 2.20-2.22 section. Do you suppose I could minimize these, if playing from an internal hard drive? (I would buy one if so...)

Also I am wondering what tool you have used to determine the variable bit rate at certain positions?
I am thinking it would be helpful for other people as well, to have the knowledge of analyzing their video files.

Once again, many thanks for your support Spawn!

[spawn]

Quote:Another side note: Is this property something you could edit in the file? What tool would you recommend, if so?

mpeg4modifier - change Display Aspect ratio to 16:9

http://www.moitah.net/

Quote:Ok. Would it be correct to say that the Popcorn isn't able to play sections with a variable bit rate of more than ~42Mbps? Neither from network, USB or the internal hard drive?

The PCH will play up to 46mbps under optimum conditions - that is if using .ts files that are purely demuxed and decoded in hardware, and from a source that can deliver the data needed. I can do this using HTTP MyIhome over my wired network, which is actually faster than the 4200 rpm mobile laptop harddrive I have in the PCH and any USB flash sticks I have ever tried with. As a general rule Id propably say yes stay below 42mbps - and for such high bitrate content stay with .ts files and h264 - this clip is Xvid in an .avi - and neither Xvid nor avi was really designed for these bitrates, nor was the PCH in terms of demuxing .avi.

Quote:Do you suppose I could minimize these, if playing from an internal hard drive?

Yes and No - even my slow mobile disc helps streaming by adding a buffer, and discs which are a litle faster than mine should give atleast the same performance as my HTTP streaming. But I still recommend keeping bitrate below 42mbps

Quote:Also I am wondering what tool you have used to determine the variable bit rate at certain positions?

I just used the info bar on the PCH - this can show bitrate while playing on the beta firmware Im running.