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1080p on iMac - Choppy, mega-lagged

A

asabove01

macrumors newbie
Original poster
Feb 19, 2009
10
0
I've read a few posts on the forums regarding this, but none of the advice has helped the 1080p or 720p mkv files I'm trying to play on my iMac look anything but horrible. Either the lag is unbearable or both the lag is unbearable and the sound is chopped up, too. Here are my system specs:

Leopard 10.5.6
2.8 Ghz iMac Intel Core 2 Duo
2 GB Ram
(I'm not sure what else you'd need)

I've tried playing the files on: Quicktime 7.6 with Perian 1.1.3, Plex, VLC, XMBC -- none of them play the files with a watchable quality. XMBC seems to hog CPU while sitting there, Quicktime goes to 105% on the CPU, Plex up to about 120--

Almost the same result on each -- extremely choppy, laggy video and sound.

I'm at my wits end with media software coming out of my ears and nothing has helped. Can anyone offer any advice? I don't know what to do next.

Thanks,

a
:confused:
 
Compress the movie?

I was going to suggest to use VisualHub, but that guy has shut up shop. You might be able to find it somewhere else.
 
That's weird, people uses Minis as hometheater and it plays 1080p fine. Even I can play 1080p with my crappy laptop (see specs below).
 
No kidding, Hellhammer. And now I'm waiting 40 hours for visual hub to convert it just to see if it works. If anyone else has a suggestion. Please.

p
 
Hellhammer said:
That's weird, people uses Minis as hometheater and it plays 1080p fine. Even I can play 1080p with my crappy laptop (see specs below).
Click to expand...

Not all 1080p is created equal. For example, my 1.6GHz MBA rev B can play 1080p trailers from Apple while remaining entirely responsive - it's really good at it (considerably better than my previous intel 3100 graphics white macbook)


BUT I also have access to a video archive that provides 1080p files. These are 17Mbps streams and I haven't found anything at all that can play them on this or any other mac hardware I've encountered (I've not tried a Mac Pro).

Quicktime can't play them at all, because it won't play streams saved locally, only if they're actually streaming. While I have access to a connection theoretically fast enough to stream 17Mbps in reality it's unlikely and the archive don't offer it.

VLC can play them but can't use the hardware acceleration under os x, ditto MPlayer so I get pretty much the same experience the OP describes. Plex couldn't even see the files for some reason - I gave up with Plex because it made me want to cry!

I have a friend who has a quad opteron system that can't play these same files smoothly under linux again because he can't get VLC to use the acceleration features of his graphics card - basically if you don't have a player that can make use of the hardware acceleration AND some pretty hefty IO, some 1080p just doesn't seem to be doable :(, even though most you would download would be fine because a lot of it is lower bitrate, or perhaps slightly different formats/containers (? - I don't really know about that aspect of things)
 
asabove01 said:
No kidding, Hellhammer. And now I'm waiting 40 hours for visual hub to convert it just to see if it works. If anyone else has a suggestion. Please.

p
Click to expand...

:( Sad that isn't working.

For a very offtopic, does your name come from Behemoth's song called As Above So Below? I just want to know :)
 
It's all in the bitrate!

So many people think that all 1080p is born equal but it couldn't be further from the truth. The trailers you get in HD from Apple are 1080p but their bitrate is very low compared to say the Planet Earth Blu-Ray. Get a 30 second full bitrate rip of some of that and see how well a mac mini HTPC handles it - it wont. My old 2.8GHz Octo couldn't play it in OS X.

So many people will tell you that 1080p is working great on their macbooks, mac mini's and you will be left scratching your head, but your machine wouldn't have a problem either if it was playing the same thing they were.

I am looking forward to snow leopard, I am hoping it will be able to better enhance the multi core power of more recent CPU's in order to make the high bitrate 1080p experience bearable on a mac.
 
No Hellhammer, but they perhaps got their name from where I did. Related to an occult saying of sorts, the macro and the micro, etc.

Hodgeheg, maybe this is what I'm running into. Bleh. Sucks having to spend this many hours just getting to a point where something is watchable!

:(
 
Strange, I have a couple of High Definition .mkv files and they play fine in Quicktime, FrontRow, or VLC.

It could be that you're missing a codec?

Try installing Perian, if you haven't already.

You can get it free from here.

Before I got this little set of codecs for AV files I couldn't even play .mkv files outside of VLC, but now as I said I can access them through FrontRow and the playback is fine.

Edit: I really need to stop skimming and start reading ... you mention Perian, so I am at a loss. My iMac is inferior to your own and runs .mkv no problem at all. Strange.
 
Oh, and Hodgeheg, Plex also made me want to cry too. I can't believe someone would actually design something so hideously. Even if it worked in Plex, I may have just said 'forget it, this blows too much'
 
asabove01 said:
No Hellhammer, but they perhaps got their name from where I did. Related to an occult saying of sorts, the macro and the micro, etc.

Hodgeheg, maybe this is what I'm running into. Bleh. Sucks having to spend this many hours just getting to a point where something is watchable!

:(
Click to expand...

I have to do the same if I want to watch downloaded Blu-ray movies from my PS3, it doesn't support .mkv files :mad:

Yea, it's about bitrate. There is very huge differences between quality in HD movies. Like in audio files there are 128-bitrate and 256-bitrate available in iTunes.
 
Tom, is there a way I could check the bitrate of the file and share it here so we know what I'm talking about? I couldn't find it in finder or VLC.

a
 
asabove01 said:
Oh, and Hodgeheg, Plex also made me want to cry too. I can't believe someone would actually design something so hideously. Even if it worked in Plex, I may have just said 'forget it, this blows too much'
Click to expand...

I've never had a problem playing any 1080p MKVs on my 2.4GHz iMac using Plex. I've not encountered a single one yet to give me the slightest hiccup although I suppose that depending on the encoding that could be a possibility.

As for Plex, it is hands down the best media player I've ever used. I'm currently using the latest 0.7 beta and have yet to find the MKV it won't recognize and play. Perhaps it might be a user issue. There is an excellent wiki as well as really helpful user forums with devoted developers that will respond to any questions or issues you may be experiencing.
 
hodgeheg said:
Plex couldn't even see the files for some reason - I gave up with Plex because it made me want to cry!
Click to expand...

You must have been doing something wrong. Plex can read more containers and decode more codecs than any other software package available for Macs.

tom. said:
It's all in the bitrate! So many people think that all 1080p is born equal but it couldn't be further from the truth.
Click to expand...

It's not just the bit rate. It's also the codec used (MPEG2 is easy, AVC isn't), frame rate (30 fps m4v/AVC/AC3 is doable on a 2 gHz Mini), and audio format (DTS, True-HD, etc.)

So many people will tell you that 1080p is working great on their macbooks, mac mini's and you will be left scratching your head, but your machine wouldn't have a problem either if it was playing the same thing they were.
Click to expand...

You mean 95% of the Blu-ray movies out there? The only two problematic Blu-ray rips I've encountered had variable frame rates (up to 45 fps). Once I dropped those to 24 fps the problem went away. I have nearly 50 Blu-ray rips and my 2 gHz Mini handles them all, and in glorious 7.1 DTS or Dolby Digital.

I am looking forward to snow leopard, I am hoping it will be able to better enhance the multi core power of more recent CPU's in order to make the high bitrate 1080p experience bearable on a mac.
Click to expand...

You mean gpus. ;)

asabove01 said:
Oh, and Hodgeheg, Plex also made me want to cry too. I can't believe someone would actually design something so hideously. Even if it worked in Plex, I may have just said 'forget it, this blows too much'
Click to expand...

Plex is the bomb! It automatically scrapes IMDB, gives you customizable skins for artwork, transcodes DTS-HD and True-HD on the fly to DTS and AC3 DD (up to 7.1) and can handle high bit rate and frame rate Blu-ray rips. Plex is a little ugly (not as bad as it used to be, though) because of its ancestry: X Box Media Center. It is a hell of a lot less maintenance than iTunes, and plays far more video/audio codecs than QuitTime, Front Row or VLC. You just have to spend a little time learning it.

asabove01 said:
Tom, is there a way I could check the bitrate of the file and share it here so we know what I'm talking about? I couldn't find it in finder or VLC.
Click to expand...

Download MPEG Streamclip to see if it can open your container. If it can, you should be able to ID the video and audio codecs, frame rate, bit rate, etc., etc.
 
Yah, I had the same problems with playing 13Gb mkv files on my 24" 2.16 256Mb video 2Gb memory imac. I put 4Gb memory and seems VLC handles movies OK as long as I don't use any other memory intensive tasks (at some point even safari alone might take 1Gb of memory.
 
Streamclip was unable to open it, so I don't have the codec information, but here's the info I got from quicktime:

FPS:23.78-23.98
Playing FPS: Usually 8-0
Data rate - 3000-5300+ kbits/s

Is this too much load?
 
asabove01 said:
Streamclip was unable to open it, so I don't have the codec information, but here's the info I got from quicktime:

FPS:23.78-23.98
Playing FPS: Usually 8-0
Data rate - 3000-5300+ kbits/s

Is this too much load?
Click to expand...

That's nothing. Many of the Blu-ray rips I have are at 30 mbps AVC and 24 fps and my 2 gHz Mini plays them just fine. There's something else going on with your system (probably QuitTime), unless your video is encoded in some strange codec. What I don't understand is why you cannot open the file with Plex. If QT can open it, then Plex can open it.
 
Cave Man said:
That's nothing. Many of the Blu-ray rips I have are at 30 mbps AVC and 24 fps and my 2 gHz Mini plays them just fine. There's something else going on with your system (probably QuitTime), unless your video is encoded in some strange codec. What I don't understand is why you cannot open the file with Plex. If QT can open it, then Plex can open it.
Click to expand...

I can play it in Plex, but the same issue occurs, lagging with both picture and sound.

More info from VLC:

Codec: avc1
Codec Audio Stream 1: dts
Codec Audio Stream 2-3: a52

Statistics:

Input:
Read at Media: 165771 kB
Input bitrate: 13245 kb/s
Demuxed: 139367 kb/s
Streat bitrate: 16243 kb/s

Video:
Decoded Blocks: 139
Displaying frames: 40371 (and rising)
Lost frames: 116 (and rising)
Frames per second: 0 (paused)

Audio:
Decoded blocks: 7947
Played Buffers: 7928
Lost buffers: 0
 
Also, similar issues occur with all of my media players, so I doubt it's only a problem with quicktime.

:confused:
 
asabove01 said:
Data rate went up above 7000 at some point, too.
Click to expand...
If you know how long the file is supposed to be (in seconds) and how large the file is (in Megabits), just divide the filesize by duration and you get your bit-rate.

Incidentally, the conversions are as follows:

1 GB = 1024 MB = 8192 Mb

So a 1 hour file at 1 GB would clock in at 2.3 Mbps. (8192 Mb / 3600 sec)

ft

BTW, this would be the average bit rate. If you're using VBR, that would explain the up/down of the bit rate that you experienced.
 
ftaok said:
If you know how long the file is supposed to be (in seconds) and how large the file is (in Megabits), just divide the filesize by duration and you get your bit-rate.

Incidentally, the conversions are as follows:

1 GB = 1024 MB = 8192 Mb

So a 1 hour file at 1 GB would clock in at 2.3 Mbps. (8192 Mb / 3600 sec)

ft

BTW, this would be the average bit rate. If you're using VBR, that would explain the up/down of the bit rate that you experienced.
Click to expand...

This is a 1.5 hour at 8 gig. Should be around 12.13 Mbps -- is this too much load for my iMac?

I still have no resolution to this, and am really interested in having it resolved, no only for me, but because I see no other resolution online available for others with the same problem.
 
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