Problems with x264 HD Movie

Discussion in 'Apple TV and Home Theater' started by Cattywampus_, Sep 24, 2008.

  1. Cattywampus_ macrumors 6502a

    Apr 19, 2006

    I am having problems with downloaded HD movies.

    I grabbed a copy of Transformers at 1080p - after quickly realising that the Apple TV would never play this, I transcoded the MKV to a .mov using Visualhub and the Apple TV setting. Movie seems to play fine using Sapphire and I was unable to crash Backrow.

    I then downloaded all 3 of the Bourne films - this time at 720p - thinking these would be fine as there were all in and/or around 5000kbps video stream inside the MKV. I opened the files up in QuickTime Pro, then Exported to a MOV file - running a passthrough for the video and re-encoding the audio at 128kbit/sec. So I was left with a

    ~5000kbps h/x.264 Video Stream
    ~128kbps Audio Stream (AAC)

    I thought that these would play fine as ATV has a 5000kbps/128 audio limit I thought and these files all sit around that mark. But they struggle to play. Skpping through the movies causes Backrow to crash and when they do play the files can be jerky.

    I don't see why they would do this as the Transformers one I transcoded has the same properties as the Bourne files. The only thing I can think is :

    My Transformers one was encoded not using this 'High Profile' thing I Have read about and uses a 'Main Profile' and the Bourne films, although meeting the ATV specs has been encoded with the High Profile and the ATV CPU is struggling decoding it?

    Does that sound about right?

  2. gadabout macrumors member

    Sep 15, 2007
  3. Cattywampus_ thread starter macrumors 6502a

    Apr 19, 2006
    Just looked at the files in MediaInfo and the only difference between the two movies is that The Bourne movies (which were 720p MKV's that I opened in Quicktime and saved as MP4) are using the High@L3.1 profile which I think from what I have read, is the reason for the bad performance on the ATV.

    The Transformers movie I transcoded in VisualHub is using the 'Main' profile.

    Looks like high def movies grabbed off the newsgroups are not going to play on the ATV full stop. Thought I was going to save loads of time not having to rip my Blu-ray collection myself but looks like I am best doing that. Either way I am going to have to do some kind of encoding for HiDef movies.

  4. spacepower7 macrumors 68000

    May 6, 2004

    High profile is the culprit I think.

    And I'm glad to see you know abt Mediainfo Mac

    I have been studying this stuff for a few months and Dynaflash (Handbrake project) here, and Tyler from Visualhub are great resources.
  5. Cattywampus_ thread starter macrumors 6502a

    Apr 19, 2006
    Do you happen to know what the difference is between the 'High' profile and the 'Main' profile? Just a better quality of performance? Does high use technologies that are not present on the CPU in the ATV (like SSE2 for example)?
  6. dynaflash macrumors 68020

    Mar 27, 2003
    Simple. The Atv does not have near enough horsepower to play hi profile h.264. Period.

    it needs to be trancoded to play main profile. Actually Quicktime, even on a state of the art MacPro was only able to play Hi profile as of the last year or so.

    Having said that, a properly transcoded Hi Profile -> Main Profile movie should look and perform great on the atv.

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