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View Full Version : Fed up with AppleTV HD playback...is it the processor??




ryanbeljan
Jun 1, 2010, 11:29 PM
hey there. im new to these forums, but not even close to being new to trying to find a solution to my problem...so i come here begging for help.

the main problem is that my HD movies do not play smoothly. they jitter at some points (looks like a lower frame-rate for example...) and also the brightness of the screen changes for 5-10 seconds to a much brighter display, then goes back to "normal". During this brighter period, I see a lot of pixelation of the picture.

Also, I do not experience any of these issues with SD content.

This is not a network/wifi speed issue as I have tested this with movies that have been fully synced to the AppleTVs hard drive. On top of that I have a fast wireless N network setup anyway...

I have tried both using the HDMI port and the component + optical out and get the same results.

I have dozens of HD movies that I have converted (using handbrake) from mkv to mp4 files that sync and play easily on the apple tv. I start with the AppleTV preset and then have adjusted settings til no end and still havent been able to find a setting that works.

I have tried adjusting the bitrate setting anywhere from 4,000 to 7,000 and have not solved the jittery issue. At 4,000 I loose too much quality as well. 6,000 has given a good picture, except for this crappy playback issue. I have also tried Constant Quality settings from 45 to 20 and those didnt help solve the issue at all.

After it appears I have removed many of the variables, the only conclusion I can draw is that the processor of the AppleTV just cannot handle the "intense" HD movie files that are being thrown at it. It must struggle to display the image, similarly like an older computer with a slower processor would.

The icing on the cake is that I do not experience any of these issues when I playback the video within iTunes on my MacBook Pro. This is what leads me to believe it is the processor of the AppleTV that cannot handle the video file.

Any input or help someone can offer is greatly appreciated. These playback issues have been driving me crazy for a long time and I cannot find the answer....



fpnc
Jun 2, 2010, 01:04 AM
Instead of Handbrake, have you tried the QuickTime preset for the Apple TV? I just installed Perian on my 10.6.3 system, launched QuickTime Player 7, opened a sample .MKV file (Star Trek movie trailer from divx.com, 1280x544 @ 23.98fps), and selected the Apple TV export preset. This created a 720p24 QuickTime .m4v file that played fine on my Apple TV. You can also do this conversion with the free MPEG Streamclip utility (once you have installed Perian, launch MPEG Streamclip, open the MKV file, select "File" ->"Export to Other Formats" -> "Apple TV" -> "iTunes..." (button) -> "Apple TV 1280x720 HD").

If you do the same with one of your problem MKV files and then find that the file still doesn't play properly then you can probably conclude that there is something wrong with your Apple TV or the Apple TV software. In this case, I'd try a factory restore followed by an update to the newest Apple TV software (after first making certain that you have backups of all of the media files that are on your Apple TV).

zedsdead
Jun 2, 2010, 04:55 AM
The Apple TV hardware is so out of date it's pathetic. I blame the hardware.

roidy
Jun 2, 2010, 07:12 AM
Yes the ATV hardware is old but it still does exactly what it was designed to do, play back iTunes purchased content. If the OP is having problems playing iTunes store purchased HD content then there may well be a problem with his ATV but if he's having problems playing his own encoded HD content then it's more than likely a problem with his encoding method. I've got load's of self encoded HD content on my ATV and it's never fails to play. Don't ask the ATV's hardware to do more than it was designed to do and then slag it off because it dosn't do what you want it to do.

iann1982
Jun 2, 2010, 07:24 AM
I second that - have you tried using an original Apple TV movie from the store? I bet you'll find it works fine.

Sounds like it's handbrake that's at fault here.

NightStorm
Jun 2, 2010, 07:36 AM
If you're using Handbrake, I've never had a problem streaming HD content once we figured out sane values for vbv-maxrate and vbv-bufsize. There might be a few seconds of stuttering at the beginning (while it works to fill the buffer), but playback is smooth after that.

ryanbeljan
Jun 2, 2010, 08:52 AM
fpnc - I will have to try the Quicktime setting and see how that fairs. Thanks for the input.


nightstorm - what settings are you using that you have potentially solved the issue? id like to try them.

I the only HD content from Apple that I have played have been trailers, and yes, they have played just fine. I have noticed that HD movies from the iTunes store only end up being around 2-3GB...could this have something to do with it? How does Apple retain good quality while keeping a small (and apparently playable file size)??

BaldiMac
Jun 2, 2010, 09:08 AM
From the tech specs page:

H.264 and protected H.264 (from iTunes Store): Up to 5 Mbps, Progressive Main Profile (CAVLC) with AAC-LC audio up to 160 Kbps (maximum resolution: 1280 by 720 pixels at 24 fps, 960 by 540 pixels at 30 fps) in .m4v, .mp4, and .mov file formats

ryanbeljan
Jun 2, 2010, 09:11 AM
From the tech specs page:

H.264 and protected H.264 (from iTunes Store): Up to 5 Mbps, Progressive Main Profile (CAVLC) with AAC-LC audio up to 160 Kbps (maximum resolution: 1280 by 720 pixels at 24 fps, 960 by 540 pixels at 30 fps) in .m4v, .mp4, and .mov file formats

invariably i knew someone would do it....im no idiot. i know the specs.

tom1971
Jun 2, 2010, 09:19 AM
You can use XBMC to play HD files.
Here's (http://patchstick.wikispaces.com/Broadcom) more info.

BaldiMac
Jun 2, 2010, 09:23 AM
invariably i knew someone would do it....im no idiot. i know the specs.

Then why were you trying something outside the specs?

BTW, these forum have all levels of users. You don't have to be an idiot to not know the specs. I can't guess what you already know.

NightStorm
Jun 2, 2010, 09:31 AM
nightstorm - what settings are you using that you have potentially solved the issue? id like to try them.
First, if you are using Handbrake to encode HD content, I'd strongly suggest you download a nightly build as there have been a ton of changes that make the process work better. http://forum.handbrake.fr/viewtopic.php?f=6&t=15901

Then, simply use the updated AppleTV preset (vbv-maxrate and vbv-bufsize defined in advanced x264 string), changing the horizontal resolution to 1280 (if you know the source is < 24fps). Some people recommend changing anamorphic to strict, but I've kept it at loose for now.

I've used these settings with approximately 70 HDDVD and Bluray encodes and have not had any problems with playback (other than what was previously mentioned).
I the only HD content from Apple that I have played have been trailers, and yes, they have played just fine. I have noticed that HD movies from the iTunes store only end up being around 2-3GB...could this have something to do with it? How does Apple retain good quality while keeping a small (and apparently playable file size)??
My encodes range in size from 2-5GB. Just remember that Apple (and the studios) start with much higher quality sources than we do, so the encoder can compress it more efficiently.

rayward
Jun 2, 2010, 01:50 PM
First, if you are using Handbrake to encode HD content, I'd strongly suggest you download a nightly build as there have been a ton of changes that make the process work better. http://forum.handbrake.fr/viewtopic.php?f=6&t=15901

Then, simply use the updated AppleTV preset (vbv-maxrate and vbv-bufsize defined in advanced x264 string), changing the horizontal resolution to 1280 (if you know the source is < 24fps). Some people recommend changing anamorphic to strict, but I've kept it at loose for now.

I've used these settings with approximately 70 HDDVD and Bluray encodes and have not had any problems with playback (other than what was previously mentioned).

My encodes range in size from 2-5GB. Just remember that Apple (and the studios) start with much higher quality sources than we do, so the encoder can compress it more efficiently.

I do this too, but set anamorphic to "None", and make sure the resolution is 1280 x XXX. I use MediaInfo to check the framerate; it's usually 23.xxx, so I leave this as "Same as Source". I've encoded about 100 Blu Rays like this, and only a few have failed to play on my Apple TV. One episode of Band of Brothers and The Hurt Locker are two that would play on my iMac but not transfer to my Apple TV, because the bitrate got too high on occasion. I dialed this back, re-encoded and everything was fine.

eschulist
Jun 2, 2010, 02:13 PM
The nightly new builds of Handbrake are a must for HD

I had the exact same problems as you. Stutter, Pixelation, video that looked like back jpeg compression.

I ran the exact same mkv I had a terrible image with through the new build of Handbrake using the AppleTV preset + 1280 x 720 and the results are back to fabulous.

I too thought the hardware was just getting too weak because I had HD movies from a few months ago that were perfectly fine. The new ones just need to be converted correctly and there are no issues.

dynaflash
Jun 2, 2010, 02:16 PM
The nightly new builds of Handbrake are a must for HD
I second that. I have not used 0.9.4 since the day after we released it. The nightlies rock (but *could* be unstable depending ... after all they are nightlies).

ryanbeljan
Jun 2, 2010, 05:51 PM
thanks nightstorm and everyone else. I got the latest build and am doing a few tests right now with the settings you have given me.

i will see how it fairs...my only question while this is encoding is that the AppleTV preset puts the Constant Quality setting at 20....is this still what you all recommend? I have just used the Avg Bitrate setting for quite some time now....howwwwwever, that could just be one of my problems...so I will take everyone word for it.

thanks again for the help.

SurfMacJpMtb
Jun 2, 2010, 09:58 PM
My opinion is that your bit rate settings are too high for this box. With the AppleTV, 3000 is about the maximum bit rate. I use the HB AppleTV setting for my conversions.

For grins you should revisit watching a movie from a VHS tape and then you will enjoy the quality of AppleTV.

For great quality, you will probably have to watch original Blu Ray discs via a quality Blu Ray player.

MP4's, like MP3's, are not great but the are much easier to store and lug around

NightStorm
Jun 2, 2010, 10:51 PM
My opinion is that your bit rate settings are too high for this box. With the AppleTV, 3000 is about the maximum bit rate. I use the HB AppleTV setting for my conversions.

For grins you should revisit watching a movie from a VHS tape and then you will enjoy the quality of AppleTV.

For great quality, you will probably have to watch original Blu Ray discs via a quality Blu Ray player.

MP4's, like MP3's, are not great but the are much easier to store and lug around
I strongly recommend using constant quality instead of average bitrate, especially with HD sources. Let the encoder decide the most efficient way to encode the video while maintaining a given level of quality. While some people say you can use RF 22-23 with HD sources, I've had no problems streaming encodes done at RF 20 (although I wouldn't recommend anything lower, again for HD sources).

The AppleTV is much more capable than Apple claims it to be... you just have to know what the limits actually are and design your workflow around them.

ryanbeljan
Jun 4, 2010, 08:56 AM
Thanks everyone for helping out. The movies I have tested have turned out great. I am back on track with the settings you all suggested.

AppleTV savers......:cool:

NightStorm
Jun 4, 2010, 09:05 AM
Thanks everyone for helping out. The movies I have tested have turned out great. I am back on track with the settings you all suggested.

AppleTV savers......:cool:

Glad we could help!