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Video encoding. The iPad pro is significantly slower at encoding 4k video compared to my MacBook Pro.
by aloknnikhil 7y ago
Video encoding. The iPad pro is significantly slower at encoding 4k video compared to my MacBook Pro.
- deleted 7y ago[deleted]
- holstvoogd 7y agoThat makes sense, you're MBP has a pretty decent GPU to do that.
- Youden 7y agoThe quality of the GPU usually has no impact on video encoding. At best, you can use a hardware encoder that happens to come with the GPU but usually you won't want that because it comes with a compression hit compared to software.
- gambiting 7y agoIt looks like you're getting downvoted and I'm not sure why - most encoding that I do is CPU-only, GPU encoding only works for a very limited set of codecs at a limited range of presets. If you need to encode anything other than those presets CPU it is.
- ttkari 7y agoDoes this compression hit you mention also apply to encoders that use for example CUDA on Nvidia GPUs? With these there definitely are significant differences in encoding speed between different GPUs.
- Youden 7y agoThere's no reason that using CUDA inherently leads to inferior compression but I'm not aware of a CUDA-accelerated encoder that's any good relative to a pure software encoder (or even NVENC, the pure hardware encoder on an NVIDIA GPU).
- FullyFunctional 7y agoWell, it's not that simple. The CUDA model has a inherent penalty for divergent thread behavior, that is, when all threads do the same, peak performance is attained. If they all follow a different path, the result can be disastrous. The relevance to media encoding is that the higher profiles do a lot of data dependent special casing. It's no accident that the earliest CUDA Video codecs only handled the base profile. This also hurts a CPU implementation but much less.
- lostlogin 7y agoHow does a user distinguish between that being due to software versus hardware?
- aloknnikhil 7y agoHow does that matter for this comparison? The claim is that the iPad pro is as fast as the Macbook Pro. If the hardware encoder is slower than a Macbook Pro software encoder and the iPad pro is as fast as the Macbook Pro, then by that corollary, the Macbook Pro's software encoder should perform faster than its hardware encoder. Surely Apple wouldn't add a slower hardware offload and use that?
- ubercow13 7y agoWouldn’t that be hardware accelerated on the iPad? What iOS app is doing software video encoding?
- jasonvorhe 7y agoThat's because of throttling though. Your MacBook Pro has fan(s), the iPad doesn't. I'm pretty sure the iPad Pro SoC in a MacBook Pro case would be at least on par with the latest Intel-specced MBP
- rubbingalcohol 7y agoBased on what evidence? A single core Geekbench run?
- aloknnikhil 7y agoThe iPad, magically, performs well in Geekbench but has throttling issues in a real world task? I find that hard to believe.
- saurik 7y agoAs someone who has literally been running thermal tests against a random Android device for days (note: not as an expert in hardware, but as someone writing software that is causing the device to overheat), analyzing at all of the temperature sensor and power regulator debug information in spreadsheets while varying the workload, it isn't even remotely surprising to me that pegging a single core (which was the point of this benchmark) might not generate enough heat to cause thermal throttling but running a multi-threaded multi-core workload might.
- aloknnikhil 7y agoOh, I'm not talking about single core scores. I'm talking about multi-core scores. The comparison link in my original comment is claiming similar multi core scores.
- zamadatix 7y agoARM SIMD is only 128 bit isn't it? Would eat pretty heavily on video encoding speed.
- gvhst 7y agoIsn’t video encoding a multi-threaded workload?
- aloknnikhil 7y agoYes. And the Geekbench comparison I linked to in my comment claims the multi-core scores are also similar.