Apple TV 3 - Stuttering

HobeSoundDarryl said:

Unless there is some way to know what is happening within the TV, it would be easy to assume that no such conversion is occurring but then we would need to explain the 4 seconds vs. 60+. I do know that the "2" used to receive 1080p files and dynamically downscale them to 720p so I know that at least that kind of conversion programming to fit spec limits existed within the "2".

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I have a hard time believing that a small TV with a single core A5 chip and 8Gigs of memory is transcoding 35Gig movies on the fly with stunning resolution that equals an Oppo Bluray Player.

Right, but are you sure the computer to which it is linked isn't doing the heavy lifting: TV3 tells master computer that it needs the file specs adapted down to what TV3 can handle, so the computer does the work?

I know you said you checked your computer and saw no activity. However, there are lots of other posts here of people who have done the same as you, ended up with bitrates below that Hunger Games bit rate and it won't play without stuttering on TV3. I referenced one of those earlier in this thread (a guy who did the 3 Clint Eastwood Spaghetti Western films). One at just 28Mbps wouldn't play fluidly.

What you reference that he doesn't is immediately pausing the stream for a good while before starting playback. Maybe he wasn't doing that and thus catching up to the stream during playback?

I also shoot a lot of HD and, after getting the TV3, I did a lot of re-rendering from masters (export edited video to Pro Res, ran those through Handbrake). Some of those videos came in at and above 25Mbps. Some of those over 25Mbps would not play on the TV3. I had to run the Pro Res file again through HB with the quality slider adjusted a bit to get the bitrate down (I think I recall 28Mbps being the ceiling but I'm not 100% sure on that recollection). Then, they played fine.

I've still got one in iTunes that is 27.7Mbps that will play fine. So the bitrate above that is where I ran into playback problems. Of course, these are 30fps video vs. 24fps movies so there might be a little more room for the latter (on the other hand, aren't the horses in TV converting 24fps to 30fps on the fly?).

I'm not really fighting what is being posted here- just curiously pursuing a definitive answer to this question. Your information is counter to my own experience and what I've seen by many others. But it's also exciting to see that TV3 may indeed have the horses for being toe-to-toe with BD on the bitrate question.

Now if only Apple would license the modern audio standards.

HobeSoundDarryl said:

So I'm not sure what to make of the dual beliefs within in this thread. There is an argument that TV3 can smoothly play high BD bitrates well above 25Mbps and there is a counter that it can't. If there is some definitive way for someone to test this, it would be good to know for sure.

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I've shot a 120 fps benchmark video to easily spot dropped frames (if any). Will soon post more info after evaluating them (compared to the iPad 3), frame-by-frame.

Menneisyys2 said:

I've shot a 120 fps benchmark video to easily spot dropped frames (if any). Will soon post more info after evaluating them (compared to the iPad 3), frame-by-frame.

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The videos are at https://dl.dropbox.com/u/81986513/082012/sublerSubs/birds2min-ipad3.MOV and https://dl.dropbox.com/u/81986513/082012/sublerSubs/birds2min-atv3.MOV .

Both played back the optimized version of https://dl.dropbox.com/u/81986513/0...4.1_40mbps_birds copy 7.mp4.joined.2audio.m4v (see my prev. post in this thread)

Basically, unlike with the 60 fps case, I've found the two platforms behave very similar: they played back the footage just a little worse as my late 2009 2.8 GHz MBP with ML and the latest VLC.

The most visible problem I could spot (in addition to the iPad 3's severely failing to play back the unoptimized version without severe stutters when streaming) was the beginning of the video - the point where really huge demand could be put on the decoder. There, there are some visibly delayed frames. For example, if you check out the iPad 3 video, you'll notice there is a very fast burst of several, previously delayed frames at 00:21 (and, again, at 01:53). There's a complete lack of any animation three(!) times at 0:20 and 0:21 - it was there that the frames were delayed.

The ATV3 video also shows this effect to a somewhat lesser degree at 1:43. Immediately before that, there are one or two delayed frames. (Nothing changes for at least 8-9 frames; with proper playback, there should be a new frame shown every five frames in the 120fps camera video as 120fps/24fps = 5).

HobeSoundDarryl said:

Right, but are you sure the computer to which it is linked isn't doing the heavy lifting: TV3 tells master computer that it needs the file specs adapted down to what TV3 can handle, so the computer does the work?

I know you said you checked your computer and saw no activity. However, there are lots of other posts here of people who have done the same as you, ended up with bitrates below that Hunger Games bit rate and it won't play without stuttering on TV3. I referenced one of those earlier in this thread (a guy who did the 3 Clint Eastwood Spaghetti Western films). One at just 28Mbps wouldn't play fluidly.

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I remember that thread. I posted something contrary to what the OP stated. I've looked again at my MacPro during playback, there's nothing happening, 0.5% of capacity being used. That's simply the computer sending the file to the TV. On the other hand, AirVideo transcoding the same movie sent to my iPhone utilizes nearly 15% of my CPU on my computer. Now that's some transcoding.

HobeSoundDarryl said:

What you reference that he doesn't is immediately pausing the stream for a good while before starting playback. Maybe he wasn't doing that and thus catching up to the stream during playback?

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I always pause my movies before I start them on the TV. The wifi and ethernet capabilities of the system are just not built for what many of us want to do. I suspect allot of the issues people are having with high bitrate are a result of Handbrake itself. Although a good program, the system does use the x264 codec. This is NOT the same as h.264 or AVC. Remember x264 is an encoder only and encodes video into the h.264 standard. x264 can use non-standard profiles and these may or may not play properly on h.264 compatible players i.e. TV.

HobeSoundDarryl said:

I'm not really fighting what is being posted here- just curiously pursuing a definitive answer to this question. Your information is counter to my own experience and what I've seen by many others. But it's also exciting to see that TV3 may indeed have the horses for being toe-to-toe with BD on the bitrate question.

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I suspect it's a combination of codec problems and the belief that the TV can stream content over 10/100 ethernet at 12.5MB/s. Like I said I have only topped out at 4MB/s, I don't use the x264 codec, and I buffer my movies before I play them.

jlasoon said:

I suspect it's a combination of codec problems and the belief that the TV can stream content over 10/100 ethernet at 12.5MB/s. Like I said I have only topped out at 4MB/s, I don't use the x264 codec, and I buffer my movies before I play them.

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Today, I've run tests with https://dl.dropbox.com/u/81986513/0...4.1_40mbps_birds copy 7.mp4.joined.2audio.m4v (40 Mbps video + 500 kbps audio). Over Ethernet, the optimized version, which started playback after 0:09, stopped at 0:08, 0:56, 1:27, 2:19 for further buffering.

No additional buffering happened with the non-optimized version (the one that I linked to). Of course, it needed 2:13 and 2:18 (measured twice) to pre-buffer.

All in all, I don't think the ATV3 is capable of 12 Mbyte/s either over Ethernet. (My router is - my late 2009 17" happily downloads files off the net with 12+ Mbyte/s over Ethernet. Over Wi-Fi, the max. speed might be around 4 Mbyte/s.)

Menneisyys2 said:

Today, I've run tests with https://dl.dropbox.com/u/81986513/0...4.1_40mbps_birds copy 7.mp4.joined.2audio.m4v (40 Mbps video + 500 kbps audio). Over Ethernet, the optimized version, which started playback after 0:09, stopped at 0:08, 0:56, 1:27, 2:19 for further buffering.

No additional buffering happened with the non-optimized version (the one that I linked to). Of course, it needed 2:13 and 2:18 (measured twice) to pre-buffer.

All in all, I don't think the ATV3 is capable of 12 Mbyte/s either over Ethernet. (My router is - my late 2009 17" happily downloads files off the net with 12+ Mbyte/s over Ethernet. Over Wi-Fi, the max. speed might be around 4 Mbyte/s.)

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Thanks for researching this. I can stream lossless blu-ray MKVs that were remuxed using Subler to M4V from my MacMini without issues to my TV downstairs. I'm using an Airport Extreme and Netgear GS105 & GS108 switches along with Cat6 cables. My files are optimized with AAC Multi-channel active (but they also contain inactive AAC stereo and DTS).

For higher bitrate (for instance Home Alone was close to 40mbps LOL) I DO have to pause & allow the movie to buffer for a minute. If I don't use what I call the "pause trick" I will see buffering and "hiccups" every few minutes.

In short: 1) Use Ethernet via Gigabit, 2) Either don't optimize your files and wait the extra minute or two for them to pre-buffer (vs optimized pre-loading times) and you should be all set for the remainder of the movie OR 3) Optimize your videos so they pre-load faster, then use the "pause trick" for about 1 minute to let the AppleTV buffer a little longer. Movies below 25mbps shouldn't even require the "pause trick" or much pre-loading.

ThisOneHere said:

Thanks for researching this. I can stream lossless blu-ray MKVs that were remuxed using Subler to M4V from my MacMini without issues to my TV downstairs. I'm using an Airport Extreme and Netgear GS105 & GS108 switches along with Cat6 cables. My files are optimized with AAC Multi-channel active (but they also contain inactive AAC stereo and DTS).

For higher bitrate (for instance Home Alone was close to 40mbps LOL) I DO have to pause & allow the movie to buffer for a minute. If I don't use what I call the "pause trick" I will see buffering and "hiccups" every few minutes.

In short: 1) Use Ethernet via Gigabit, 2) Either don't optimize your files and wait the extra minute or two for them to pre-buffer (vs optimized pre-loading times) and you should be all set for the remainder of the movie OR 3) Optimize your videos so they pre-load faster, then use the "pause trick" for about 1 minute to let the AppleTV buffer a little longer. Movies below 25mbps shouldn't even require the "pause trick" or much pre-loading.

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You throw DTS in a M4V? I didn't think that was a standard audio format for that container.

jozeppy26 said:

You throw DTS in a M4V? I didn't think that was a standard audio format for that container.

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Yes, M4V supports DTS but most M4V capable devices can't "see" the DTS track. I can however preserve the format for future use and ditch the original ISO or MKV.

I generally convert my DTS-MA HD files to AC3 @ 640kbps, setting the order as:

1) AAC Stereo (Enabled)
2) AC3 (Unchecked)
3) DTS-MA HD (Unchecked).

The Apple TV will see only AAC Stereo and AC3, and since AC3 is Audio Track #2, Apple TV will automatically play AC3 on my downstairs AV receiver with "Dolby Digital: On" enabled in the aTV settings, but on my stereo TV upstairs it'll play stereo automatically. It's the "best of both worlds".

That said I think it's an issue with the Apple TV itself since I recently bought a "rev 2" ATV3 for downstairs, retiring the "rev1" ATV3 to the bedroom and haven't had any skipping issues since (downstairs), yet the bedroom barely can handle even starting the file now that it's over WiFi instead of Cat6.

ThisOneHere said:

Yes, M4V supports DTS but most M4V capable devices can't "see" the DTS track. I can however preserve the format for future use and ditch the original ISO or MKV.

I generally convert my DTS-MA HD files to AC3 @ 640kbps, setting the order as:

1) AAC Stereo (Enabled)
2) AC3 (Unchecked)
3) DTS-MA HD (Unchecked).

The Apple TV will see only AAC Stereo and AC3, and since AC3 is Audio Track #2, Apple TV will automatically play AC3 on my downstairs AV receiver with "Dolby Digital: On" enabled in the aTV settings, but on my stereo TV upstairs it'll play stereo automatically. It's the "best of both worlds".

That said I think it's an issue with the Apple TV itself since I recently bought a "rev 2" ATV3 for downstairs, retiring the "rev1" ATV3 to the bedroom and haven't had any skipping issues since (downstairs), yet the bedroom barely can handle even starting the file now that it's over WiFi instead of Cat6.

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My Samsung TV freaks out and prompts me with error messages when it sees DTS audio in a .MP4 container. Completely fine with it in .MKV (and fine with AC3 in .MP4). Strange.