HD Extender MP4 Choppy Playback

[Taddeusz]

I hate to create a new thread because I believe I've seen this metioned elsewhere. I just received my new HD Extender and got it hooked up and updated the firmware. So far I love it. Nicer quality than my MVP. I do have one problem though.

I have a bunch of DVD movies I've converted to AVI format with H.264 video and AC3 audio. When I play them they take a few seconds to begin playback and once they begin playing the video is playing really fast. After a few seconds the video slows down but is very choppy and is out of sync with the audio.

Anyone have any ideas what's going on?

[Taddeusz]

Well, just to bump this a little I've been doing some experimentation. I encoded the same segment of a movie several times in a few different formats. All with H.264 video. An AVI with AC3 audio didn't play properly. Standard MP4 wrapper files with 5.1 channel and 2 channel AAC audio. Both played ok but the 5.1 channel AAC got downmixed to stereo. Lastly I tried an MKV wrapper with AC3 audio. This actually worked perfectly! Video and audio are playing at the correct speed without choppiness!

BTW, I'm using Handbrake to convert my movies. Unless they fix the problem with the other files rather quickly I suppose I'll end up re-converting all my existing AVI files into MKV format. Anyone know if there is an easy way to do this without having to totally re-encode them by maybe remuxing them into MKV?

[parkimar]

Thanks for posting - I've also got a number of .mp4 files created using Nero, which have 5.1 AAC and I found that the extender down mixed them to stereo.
I posted it in a separate thread - but no one responded.

I'll try re-encoding a test to MKV and see how it works on mine.

Cheers

Mark

[Taddeusz]

Well, I encoded a full movie into MKV with AC3 audio (since AAC gets mixed down to stereo). A couple caveats. While the movie plays fine if you attempt to fastforward at all it jumps back to the beginning of the movie. The other is that while all the AVI with AC3 audio that I already have play fine on my regular client the MKV doesn't and freezes it with the spinny circle of death.

[Taddeusz]

I've submitted a support request.

Personally, I expected there to be a few problems. With a company the size of Frey it's going to be difficult to fully test something like this before it goes to market.

I'm not at all displeased. In fact, despite the problems I've very satisfied so far after my first evening with it. SD video recorded from either my PVR cards or HDHR looks excellent. HD video recorded from my HDHR looks excellent and plays back smoothly. Most other videos I have play fine and look excellent. They look even better than they did on the MVP in high quality mode with no obvious macro blocking. I was even able to do DTS pass-through on a ripped DVD!

Overall this is a good product that needs a few wrinkles ironed out so it can become a great product! I'm sure the problems will continue to be ironed out as has been done with SageTV itself.

[rajczi]

I have three HD extenders running against a 6.3.5 server that I built last week as an overall new system. I am having some issues with the playback on the extenders, but this is to be expected with any early adopter hardware/software. The potential of the extenders is undeniable and more importantly, the Sage crew has been very responsive (24hr turn around) on every email I have sent with a question. Even more important then Sage support is that my wife is hooked!

I have not seen anything that rates higher then an early adopter glitch. That is not to say that some of them are not majorly annoying, but I am sure they will all get worked through in the end.

I would not recommend to anyone that they re-encode (or even re-mux) their entire collection for at least 6 weeks or so to see if the next couple of firmware releases resolve any specific video/audio (especially surround sound) issues they have.

Just my 2c for free...

[flloyd]

Originally Posted by Taddeusz

I suppose I'll end up re-converting all my existing AVI files into MKV format. Anyone know if there is an easy way to do this without having to totally re-encode them by maybe remuxing them into MKV?

AVI-Mux GUI looks like it should do what you're looking for.

[Taddeusz]

I think I'm going to hold off re-converting my videos for a bit. See if they resolve the issue with playback first. If I re-mux to MKV now I'll be basically trading one problem for another. It would be nice if they both worked but I can wait at least a short time.

I'm not so worried about the AAC 5.1 audio. I'm just guessing that the extender is automatically converting it to PCM stereo since most receivers can't decode it. I know mine can't, it's just a tad too old. Besides, there's not that much size difference between a file with AAC 5.1 and a file with AC3 5.1. You're talking about 384Kb/s versus 448Kb/s. Not enough to worry about. Besides it will sound better since the AC3 audio isn't being transcoded like it is going to AAC. It would be neat if Handbrake would do a pass-through for DTS audio like it does for AC3.

[VikingCrown]

I've been having .mp4 issues as well. I have several movies converted to mp4 with AAC and 5.1 surround using Nero and I am getting zero audio from playback on the HD extender, but they play fine on my client PC. Does anyone have any suggestions or thoughts?

[Nadim]

My aac 5.1 files get downmixed to stereo also. Hope they post a fix.

[reggie14]

Originally Posted by Nadim

My aac 5.1 files get downmixed to stereo also. Hope they post a fix.

Out of curiosity, what receiver do you have? My understanding is that AAC-capable receivers are few and far between.

[_Demo_]

Could you give details how those files were made. We have not been able to reproduce this issue.

Thanks

_Demo_

[Taddeusz]

I use the latest version of Handbrake for Windows directly off my original DVD's. I tell it to make AVI files with AVC/H.264 video (I believe it uses x264 for encoding) and pass-through AC3, which means it uses the original audio from the DVD without any kind of modification. The MKV file was created in exactly the same way. The only difference being the destination container type.

[Nadim]

I have a Denon AVR-3805 which used to be one of thier flagship
models a few years back. This is a high quality receiver/amp so
I am sure it is not a problem. It has lights to show how many channels
are coming in, and another set for going out. That is how I know
stuff is coming in stero. Not sure it does native AAC but most of
the recievers in the market only do PCM AC3 or DTS. Then again a transcode of the sound should be possible.

[Taddeusz]

After playing some other different files, like some low quality MOV's that I have that aren't natively supported, it appears that SageTV assumes that the HD Extender can natively play everything instead of determining if the file being requested needs to be transcoded or not. I would think it should be smarter than that.

[Taddeusz]

Well, this latest firmware update mostly fixed the problem. I noticed there is an issue of playback of files that have a frame rate of 29.97fps. Their playback is a little jittery but not terribly so. Just not exactly as smooth as it should be. Files at 24fps seem to play back perfectly.

[Taddeusz]

For anyone who is still watching this thread I think I've figured out one of the problems I've been having with my H.264 AVI files. I ran across a thread on Handbrake's forums and someone mentioned that AVI is not a good container for H.264 because AVI is old and does not "see" the more advanced features such as Pyramidal B-Frames.

Well, I've been playing around with the advanced x264 settings in Handbrake this evening because of that statement and noticed that AVI files were playing back really choppy on both computer and HD Ext. I changed to an MKV wrapper and all of a sudden the same exact H.264 stream played perfectly without stutters.

Then I tried encoding a 29.97fps video that was playing with micro-stutters on the HD Ext in an MKV wrapper. Guess what, it fixed the micro-stutters. Plays perfectly.

So, after encoding about 65 movies in AVI H.264/AC3 I've decided it's not the correct wrapper to be using for the job. Plus I've been playing around with the encoder settings and hopefully have it set so I'll get better quality out of it.

For reference here are the x264 settings I'm using which seem to be working great in Handbrake.

ref=3:bframes=3:subq=6:me=umh:mixed-refs=1:weightb=1:brdo=1:analyse=all:no-fast-pskip=1

The only problem I've noticed is that they don't play through Placeshifter. I'm about to test without Pyramidal B-Frames to see what happens.

[Taddeusz]

I just tested without Pyramidal B-Frames and it still doesn't play. I guess that setting doesn't matter as far as the transcoder is concerned.

[valnar]

I don't have my HD Extender yet but I plan on using AutoMKV because it does a little more than Handbrake. There is a PS3-41 (something like that) profile which looks like it should be the one that works best, but I can't test it yet. It does not use Pyramidal B-frames either and have some other limitations which hopefully improve compatibility. Give it a shot.

robert

[Taddeusz]

I'll give it a try. The main reason I've been using Handbrake is that there are both Windows and Mac versions.