mp4 Question/Problem

[dmichaud]

So I convert all my media to mp4 as I have found tv shows / movies to play best from my QNAP NAS device in this format. Lately ive run into a strange issue. Almost all of them are HD 720/1080.


Various movies/tv shows seem a bit laggy or choppy - very subtle but none the less noticeable. It lasts generally for the first few minutes, then it goes away and the media plays fine. Its weird. Like its dropping frames or something...hard to explain. The sound doesnt appear to be affected.


Size doesnt appear to be an issue, I have a 30GB mp4 files that plays flawlessly, however a 800MB file of a TV show that has this choppy/lag effect for the first 2-3 min. I should note in all cases after a few min it goes away and the media plays with no issue.


I have a qnap 869L with 8 4TB enterprise drives, 3GB ram. Its wired to home network and hooked to my tv via HDMI.


It appears most these files play without issue on VLC, when I play them in quicktime they have the same problem as xbmc via the NAS. I dont know if I should try reencoding some of them or not. I have played around with it but seem to get the same results. I am on a mac, and while I have various software I am somewhat new to this maybe there is a software tool that can inspect the video files.


Any advice?

[Baldrick]

What do you convert with? What settings?

[dmichaud]

I use either Wondershare Video Converter Ultimate or Xilisoft Converter. As far as settings, I generally try to keep them what they originally were. I use Mediainfo to get the video information and then change the settings in the converter where I can. I dont really tinker with the settings much. Ive tried different ones out to see if I could improve it any. Ive started to get in the habit of simply remux the files to mp4 without converting anything.

[Baldrick]

Try instead handbrake or vidcoder. Use the normal preset.

[dmichaud]

So I found an old forum post and I am not sure what it means:

If you're having trouble with your high definition videos and they're encoded with the H.264 codec then you might want to try this: Preferences -> (tab) Input / Codecs -> (tab) Other codecs -> FFmpeg -> (tick "Advanced options" box) in the drop-list next to "Skip the loop filter for H.264 decoding" select "All", save and restart VLC.


I did the above and the video no longer stutters or lags at the start. What does that mean? I mean Does that tell you anything about correcting the other videos? While I am happy it sorted it, I am playing these on a HD TV....I dont really care if they work in VLC.

[Hoser Rob]

"I am playing these on a HD TV....I dont really care if they work in VLC" ... I don't get that 100% ... if you're playing via a media player to TV you should definitely care ...

Disabling the loop filter for h.264 is an option provided for playing high bit rate h.264 video on older or less powerful hardware. It's a bit of a kludge since it can cause distortion.

... OK, I just did a search on the qnap 869L and apparently the CPU is an Intel Atom D2700.

I hate to say this but that is not a very powerful CPU and I am not surprised that disabling the h.264 loop filter would help with 720p or 1080p video.

Also look into settings like allow frame drop and/or hard frame drop. Also double buffering.

Actually, speaking of buffering, vlc as of version no longer supports decent caching for local files. IMO this is really moronic as it means you can't get good performance on slower hardware. I use smplayer with the local file stream cache set at 8192Kb.

[dmichaud]

would playing the movie via htpc help? Just use the nas for storage instead? I am getting an intel haswell nuc, I was hoping it would help.