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989 posts

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  Reply # 875562 12-Aug-2013 02:07
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jiranz: MKV files play OK. I downloaded samples from the divx site and it plays them. It doesn't recognise the .divx extension files. The problem seems to be with AVI files which say they were encoded with xvid. I have converted some of these to FLV and MP4 and then they will play OK. I did not know to convert them to MKV but i have a program which does that just as easily. I think I just have to get stuck in and convert everything. Our family camcorder records in AVI format and that means a lot of videos to convert and it will be ongoing for years to come.

I did not realise that the decoder might be a hardware chip. I have been blaming the linux OS because i had assumed that codecs were downloaded with OS firmware updates like you can download Klite codecs for use with Windows programs. I can see its complicated. If it is hardware related for sure then I would have no problem going back to the suppliers again. I wish I knew how to find out for certain.


OK - so it plays the files from the divx site without problem so that says that there is no problem with your player. In all probability the problem is with your original files. If they are being generated by your camcorder then you might want to take a look closely at its settings and see what can be adjusted. It may be possible to record to a different format or it may be possible to adjust the settings and continue using xvid/divx. (often, audio sync issues can be caused by the audio being saved in a variable bitrate. Audio within video files should really be saved at a constant or average bitrate)

If you are going to re-encode the files I'd suggest saving them as h264 (avc) in either an avi, mp4 or mkv container. (using aac or ac3 as the audio encoder)
If they are just basic video files then it doesn't really matter which container you use.
There are a number of tools that will do this for you. I'd suggest Avidemux. It is an easy to use, free tool that can batch process all your files.

However, it may not be necessary to re-encode all your files. It may simply be a matter of making some minor adjustments to them. Again, if we could see a sample this may help.

Trust me, your issues will have nothing whatsoever to do with the fact that the player you are using is Linux based. I have been a Linux user for many years and have no problem with viewing all sorts of video content. Usually I have much less trouble with various file formats than my Windows friends and colleagues. If I come across a file that wont play correctly on my Linux machine 99.99999% of the time it is the fault of the file.



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  Reply # 875640 12-Aug-2013 09:59
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So the end logic is that the files must be faulty because they will not play properly on my machine.
Logic would then suggest that all the machines that do play them faultlessly must be faulty !!!
(In that case i wish i had bought a faulty machine in the first place!)

Next, I am going to try the Serviio Renderer solution so we can bypass the codecs in the box. I am getting help on their forums to see if i can make it work but the technical challenge is a bit scary for me!

I just want to do this as an experiment but logic again says there is no logic in buying a machine that will not play files that anyone else can play and then utilizing a separate pc to render the files to produce the illusion of them playing through the machine which will not play them!
I guess I am replacing one codec with an entire PC.
It's kind of funny in an ironic way.

There is an obvious solution but it's probably the last one I want consider!
Thanks for your and everyone's help on this.
You are right, It does come down to playing one file type on one machine.
It's a non-working combination and i happen to have it.

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  Reply # 875674 12-Aug-2013 10:45
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It would be a good test to chuck a couple of the 'problem' files at another sort of media player and see what it does with them - As I mentioned they tend to have the decoder function on a chip - (like your PVR I expect) - If it plays ok on something else (not a PC) then it points back to the PVR.

It sounds like the PVR it will cope with some divx/xvid files ok - you had some that worked ok - so the workaround may be (as farcus has wisely indicated above) to try and find out exactly what it will cope with and if you hit that magical hotspot then there wont be an issue. It may be a bit of a kludge but may be the easiest thing to do. Is it just video files you have recorded from your camera that are the issue??? If so - yep try and see if you can tweak the camera settings.

Its worth doing a little research on containers (mkv/mp4/avi) and the different sorts of content they support (audio video codecs) just for your own knowledge - its quite interesting really.

As I said there is usually a decoder chip that has all the smarts for decoding video files in media boxes- the chip manufacturers have an SDK (software Development Kit) that the PVR manufacturer would use to have their software (linux usually) interface with the decoder chip. So its possible there could be an issue with the SDK, the firmware on the chip or the linux software might not be using the SDK kit correctly or maybe there is a later version of the SDK that they should be using.
I learnt some of this stuff after having a Playon HD media player and witnessing various issues come and go as they released different versions of software for it - its still possible that the manufacturer needs to rectify the problem.




Nothing is impossible for the man who doesn't have to do it himself - A. H. Weiler

989 posts

Ultimate Geek
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  Reply # 875885 12-Aug-2013 15:01
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jiranz:
So the end logic is that the files must be faulty because they will not play properly on my machine.
Logic would then suggest that all the machines that do play them faultlessly must be faulty !!!
(In that case i wish i had bought a faulty machine in the first place!)


as mentioned earlier - tolerance of improperly encoded files varies greatly between players - especially players like media player classic that will play almost anything you throw at them.


. . . You are right, It does come down to playing one file type on one machine.
It's a non-working combination and i happen to have it.


actually it seems more specific than that. The issue appears to be for one file type generated from one particular source.
an extensive search for other users of the same machine doesn't turn up any results of the same issue - so it does seem that the problem is specific to you. To my mind, the camcorder seems the obvious culprit as we have already established that divx files from another source play fine.

edit:
Next, I am going to try the Serviio Renderer solution so we can bypass the codecs in the box. I am getting help on their forums to see if i can make it work but the technical challenge is a bit scary for me!


this may be a good solution that avoids the need to re-encode the files.



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  Reply # 875967 12-Aug-2013 16:07
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No. It's not just my files..
I have other files sent to me by friends which do the same thing on playback.

Properties
Width = 368 pixels
Height = 272 Pixels
Audio
Duration = 0:43:20
Bit Rate = 96bps
Audio Format = MPEG Layer-3
Video
Frame rate = 23 fps
Data Rate = 520kbps
Video Sample size = 24bit
Video Compression = XVID

The good news is that the Serviio solution worked just with a generic install.
I thought it was going to be difficult but I didn't have to tweak anything.
I must have been lucky that the defaults just worked in my case.

Its a solution so we can watch our videos but it means we must have the PC running all the time.

989 posts

Ultimate Geek
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  Reply # 875989 12-Aug-2013 16:42
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jiranz: No. It's not just my files..
I have other files sent to me by friends which do the same thing on playback.

Properties
Width = 368 pixels
Height = 272 Pixels
Audio
Duration = 0:43:20
Bit Rate = 96bps
Audio Format = MPEG Layer-3
Video
Frame rate = 23 fps
Data Rate = 520kbps
Video Sample size = 24bit
Video Compression = XVID


there's note really very much there that is useful information as it is just the metadata.
Although - they do appear to be very low spec files, but that should not be causing your issue.

One thing that could be worth trying is just re-encoding the audio in the files to something other than mp3 (aac or ac3).
Probably not the cause but I guess there is a chance that if they are vbr mp3 files that could possibly be the problem.

The good news is that the Serviio solution worked just with a generic install.
I thought it was going to be difficult but I didn't have to tweak anything.
I must have been lucky that the defaults just worked in my case.

Its a solution so we can watch our videos but it means we must have the PC running all the time.


good that this has worked out. At least you can now watch the vids without problem.

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  Reply # 876622 13-Aug-2013 17:43
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In the time you've spent fafing around looking for a fix you could have downloaded freemake and recoded the vids to .mp4 from (xvid).avi format in about 20mns or less depending on CPU speed

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  Reply # 876678 13-Aug-2013 18:56
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jiranz: No. It's not just my files. I have other files sent to me by friends which do the same thing

[...]

Frame rate = 23 fps

[...]



I have a sneaky suspicion the 23 fps in that list is your problem. It isn't a standard framerate. Most decent players will cope with 29.97 fps (NTSC), 25 fps (PAL) and 24 fps (some ripped films). Anything else can be hit and miss.

Modern camcorders etc shouldn't be spitting out anything at 23 fps. Nothing recorded from TV, ripped from disk etc should have this rate either. Where is this material originating from?



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  Reply # 876712 13-Aug-2013 19:54
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Athlonite: In the time you've spent fafing around looking for a fix you could have downloaded freemake and recoded the vids to .mp4 from (xvid).avi format in about 20mns or less depending on CPU speed


Yes of course. I always could play the files through my pc using its hdmi interface. Being able to view the files was never an issue.

The query is because these exact files play on any other equipment I can access. It is only on this particular brand of pvr that there is any problem.

The real issue is that I was trying to decide if the files were faulty or if the codec chip/software is faulty in this equipment which is still in warranty. It was very expensive and it seemed to me that it might be faulty.

I bought it a year ago but it never worked properly. I tried to discuss it with the suppliers but they were not helpful and put it back on me. I then got frustrated, my family and friends told me i had bought a lemon until I threw it in a cupboard for a year and used a DishTV sat box instead which was simple for them to operate.

Then a couple of weeks ago (about), i happened by chance to find the original purchase receipt and saw that it had a 2 year warranty. So i got it out of storage, fired it up and set about figuring out what is wrong with it.

I wrote down all the faults and handed it back to the suppliers who confirmed that one of its two tuners was faulty. That explained the empty files it was saving and a few other problems like saving the wrong channels (which i have not previously mentioned here). I also told them about the audio/video sync problem (which is my immediate area of interest here) and gave them sample files which demonstrated the problem. They handed it back to me (arrived in the post) without any attempt to address that problem. I believe the people selling it here are genuine but lack the technical expertise to handle deep problems.

So I turned to these forums in the hope of gaining access to expertise which might help me to understand what this problem is so i can take it back to the supplier. All input is gratefully received. I am no expert but it seemed to me that by an application of logic it should be possible to reach a reasonable conclusion as to where the problem lies.

That is what this forum is about.
I am sorry if you gained the impression I was just trying to make damaged files work.
Thanks for your input.



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  Reply # 876727 13-Aug-2013 20:19
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Modern camcorders etc shouldn't be spitting out anything at 23 fps. Nothing recorded from TV, ripped from disk etc should have this rate either. Where is this material originating from?



Width = 368 pixels
Height = 272
Data Rate = 520kbps


a modern camera (from the past 5 to 10 years) shouldn't be outputting something at this spec either (unless the user has specifically set the camera to something this low)

even a low res TV show rip in xvid format will have a res of 640x352 and a bitrate of about 1100kbps

sorry - but all signs so far point to file trouble and not hardware trouble.

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  Reply # 876736 13-Aug-2013 20:45
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Nothing to be sorry about - your posts have been entirely reasonable and they are the sort of thing that this site is all about.

Athlonites post is quite blunt and could seem rather dismissive - I suspect its just in the style of a quick post and I dont think you need to read more into it than a quick point of view.

23fps with packed bitstream used to be a problem with dvd/media players etc that used to handle xvid files - It used to show up as jerky movement especially obvious with horizontal scrolling. I mentioned using mpeg4modifier to unpack the bitstream (if packed) - did you have a play with that?

JimmyH could be right about the 23fps being an issue - the other fps rates he mentions are more common. It could be your player is not coping well with 23 and is playing then back at 25 and therefore the video would get ahead of the audio. To try and match the screen players can try and drop frames etc to match the 50 hz (PAL) or 60hz (NTSC) systems - you can give yourself a headache trying to read about it here:
http://en.wikipedia.org/wiki/Telecine

I think you need to dig around your files and find out the specs of the files that work ok and those that dont and work out what the factors are. Once you have that info post it and see if anyone has any ideas.




Nothing is impossible for the man who doesn't have to do it himself - A. H. Weiler

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  Reply # 876738 13-Aug-2013 20:49
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23 fps would normally be 23.976 (sometimes called 24fps) which would indicate something from a film source.
If its really straight 23fps thats a bit non standard. Could be windows showing the rate 23.976 truncated.




Nothing is impossible for the man who doesn't have to do it himself - A. H. Weiler



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  Reply # 876906 14-Aug-2013 09:41
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robjg63: ...
23fps with packed bitstream used to be a problem with dvd/media players etc that used to handle xvid files - It used to show up as jerky movement especially obvious with horizontal scrolling. I mentioned using mpeg4modifier to unpack the bitstream (if packed) - did you have a play with that?

I think you need to dig around your files and find out the specs of the files that work ok and those that dont and work out what the factors are. Once you have that info post it and see if anyone has any ideas.


Using MPEG4 Modifier - Here are two files that play wrong on my pvr but OK on my pc.
(I didn't know what to do so i clicked on Video Info)

File #1
Packed bitstream:  YesQPel:              NoGMC:               NoInterlaced:        NoAspect ratio:      Square pixelsQuant type:        H.263FourCC:            DX50User data:         DivX503b1328pI-VOPs: 2840 (2.15%)P-VOPs: 79537 (60.13%)B-VOPs: 49888 (37.72%)S-VOPs: 0 (0.00%)N-VOPs: 0 (0.00%)Max consecutive B-VOPs:   1

File #2
Packed bitstream:  YesQPel:              NoGMC:               NoInterlaced:        NoAspect ratio:      Square pixelsQuant type:        H.263FourCC:            DX50User data:         DivX503b1328pI-VOPs: 1441 (2.18%)P-VOPs: 38193 (57.82%)B-VOPs: 26424 (40.00%)S-VOPs: 0 (0.00%)N-VOPs: 0 (0.00%)Max consecutive B-VOPs:   1

I noticed that mpeg4modifier says it is divx encoding but windows properties says it is xvid. Maybe that distinction is not so important after all? I thought it must indicate two different worlds apart.

Are these really such poor quality as suggested here? Both files play on the pvr in acceptable quality for viewing on the large TV screen There is no pixeling or color problems and they do not seem to jerk.
I am not sure how it achieves it but the pvr player plays/renders them as 1080P. Maybe that is a default just to do with the screen size but it puts up a little popup window at the start stating how it is playing videos. Or maybe again that is something the large screen manipulates on the fly.

On my PC screen which is a Dell 27" monitor the above two files look very acceptable on playback. Having come from the days of holding a wooden cross with fencing wire antennas stapled to it whilst walking up a hillside trying to get the first black and white transmissions out of snow, maybe my perceptions of quality involve a much lower expectation!

The difference of course is that on the tv the sound gets out of sync.

What changes should i make to the above figures to test the tweak theory?

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  Reply # 877007 14-Aug-2013 11:29
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Your PC and the media player (PVR) will upscale the video to fit the display.
Depending on how they do it they can make a pretty good job of boosting the picture quality (within reason). If it looks ok there isnt a problem.

What results do you get from mpeg4modifier on a file that plays ok? - that might be useful to know. Make sure its a file that you know is xvid rather than divx.

I gather the tags info dictates information for the codec - so I would expect that 'maybe' changing these *may* make a difference. I am not an expert on any of this....
But please take a copy of one of your files before tinkering though.

Firstly I would try and click the 'unpack bitstream' checkbox and save the file - please dont hold your breath that this will fix it though - but its worth a shot.
It saves the file almost immediately - it just sets a switch in the file.

I dont profess to know exactly what values you can use for the tags - but this forum (the mpeg4modifier forum) has some talk:
http://forum.doom9.org/showthread.php?t=78050

Post number 10 says ...
"- adding "old xvid" identification, which will make new xvid decode old (xvid .9) streams correctly. These streams do not have any userdata, and xvid assumes iso mpeg-4, but they are broken. If xvid can identify them with proper userdata, it would apply a workaround and decode them good.
The userdata for that is "XviD0001".

You could try changing this info in the file and see if it makes a difference - there is a chance (maybe small) that changing the user data flags to something that the PVR codec likes might make a difference.




Nothing is impossible for the man who doesn't have to do it himself - A. H. Weiler

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  Reply # 878146 14-Aug-2013 15:04
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What changes should i make to the above figures to test the tweak theory?


my money is on bad audio or packed bitstream.
Try fixing those one at a time.
First try unpacking the bitstream and if that doesn't work try re-encoding the audio to something at a constant bitrate.

Are these really such poor quality as suggested here?


yes, at that bitrate and resolution they would be considered a poor quality video/audio file - but as Robig63 said, if they look fine to you then don't worry about it. It would not be the root cause of your problem.

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