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View Full Version : Most rencodes of H.264 to HEVC found on the internet have choppy video/hiccups. Why?


tobindac
8th January 2017, 18:55
Has anyone else noticed this phenomenon? Literally every single video I find that is a reencode from an original H.264 seems to lose 1 frame ever 3-4 frames making an extremely choppy video playing experience. It's especially noticeable with SVP but even with it disabled it's worse.

I guess they do something wrong when encoding. I can't easily believe it's the codec's problem itself. It's too obvious to be programmer's error.

tobindac
8th January 2017, 19:10
And no, it's not the PC, it's an i7-4790k overclocked with an R9 290.

sneaker_ger
8th January 2017, 19:34
No idea what you are talking about. Post a sample. Show renderer statistic, MediaInfo log, CPU/GPU usage, video decoder and player settings.

birdie
8th January 2017, 20:02
Are you quoting the scene? If you are then only few people do such encodes and it might be quite possible they use some fancy utilities/old buggy versions of x265 which lose frames while reencoding. And since those reencodes hardly receive any attention the guys behind them are in the unknown.

(However I have to admit I watched several series of Westworld in HEVC and I didn't notice anything odd).

Also it's quite possible your decoder is buggy.

Anyways, without hard data (examples and media info) it's hard to say.

Groucho2004
8th January 2017, 20:07
No idea what you are talking about. Post a sample. Show renderer statistic, MediaInfo log, CPU/GPU usage, video decoder and player settings.
Not to mention the rather ambiguous "found on the internet" comment. If you download stuff encoded by morons - shit happens. Also, just in case, read the forum rules, particularly #6.

tobindac
9th January 2017, 00:45
I know they might be morons. But it is pretty odd that every single "scene" sample I've checked has choppy playback. I doubt my decoder is buggy, it's on the latest mpc-hc nightly build and latest madVR (and occasionally SVP) for years and the same thing happens with all the current versions of that time.

I don't want to insult anyone (like they insulted me) but are you sure you know if a video has hiccups in FPS? It might be possible to miss them. It's very easy for me to spot lost frames every 5-6 frames or less since I regularly use SVP and I'm very used to smooth playback by now.

Problem is literally everything on HEVC that is a re-encode (all "scene" samples, I doubt any tv show is originally released in HEVC) looks choppy/with hiccups.

tobindac
9th January 2017, 00:49
And something else, my impression is that that the lost frames are not during playback but during encoding, meaning the madvr stats might show no dropped frames but still see hiccups on the end result.

tobindac
9th January 2017, 17:31
I think I start detecting where the problem is, and it's not x265 per se or their encoding exactly. Certain sources they use of lower resolution, say regular 720p, work fine on their x264 form and do look fine in terms of smooth succession of frames on x265. However, a very large number of 1080p files based on HDTV sources have the issue, and the key factor is they often have that issue on the original source as well.

tl;dr: a large number of 1080p HD TV H.264 samples circulating the web are just crap, they often have hiccups or other issues in frame succession, and a H.265 re-encode can not fix them.

Playback dropping frames has nothing to do with it, it's a source issue strictly:

https://i.imgur.com/ZRS5VGw.png

kuchikirukia
13th January 2017, 11:26
So don't watch them.

tobindac
17th January 2017, 21:25
So don't watch them.
Of course. It's just impressive to the point I wasn't sure at first if it's even that widespread as a problem of the source and not of the technology. Since it's not the technology's fault I guess it can cause it to have bad reputation.

Luckily I notice they gradually become rare to have that issue.

It's mainly the TV streams that have the issue but still.