Hi everyone,

I had posted a topic earlier in the week regarding some Front End issues I had attributed to XvMC. My decison at the time was to ditch XvMC and go with a hardware upgrade. After giving it some thought, I'm wondering if my network or even backend may be an issue.

Anyone on this forum using a backend to capture HD and a separate networked Front End to play it? I only ask because I'm not certain what role the backend plays for playback (i.e. does it handle FF or RWD, and/or commercial skip?) or it is all done of the Front End. My current backend is a Dell 400SC 2.4 dual core with 1 Gig RAM.

Also, is a 100 Mb network sufficient to play HDTV?

As always, thanks in advance.

I played with a split FE/BE for HDTV playback. 2.4gh dual core is more than enough housepower for the backend. 100MB wired network is fine for the connection between FE & BE.

I ran a split config for a few days. The backend was a P3-500mhz system; front-end was a P4-2.4ghz non-HT system. I ran into pre-buffering pause problems on the front-end with 1080i recordings; 720p and 480i recordings played back fine. My final assessment was that my front-end was underpowered. I believe it would have worked OK if I had increased the front-end to a faster processor, although I never ran that experiment.

Marc

I've done remote front end HDTV playback, both with a Athlon XP 2400+ (using XvMC) and currently with a Roku HD1000 running MythRoku. Playback with 100BaseT is fine. I mainly watched 720p programs on the Athlon front end so not sure how it did with 1080i... the Roku plays back both perfectly.

I just re-read both of your posts. Some additional thoughts:

1. You never state of your network is wired or wireless. If wireless, you will likely have flakey behaviour.

2. Make sure you aren't using any hubs in your network -- hubs reduce speed to 10 mbps.

3. Make sure your FE and BE are plugged into the same switch.

4. Check your myth frontend log for any error message like "pre-buffering pause".

5. I tried configuring my front-end machine as a remote front-end and as a slave-back-end. I found that configuring the front end as a "slave backend" worked better than configuring it as a remote front-end. It looked to me that a slave-back-end uses a bit less CPU power for playback than a remote front-end. Look at the "LINHES" configuration if you want to try this configuration.
Marc

I am running a split HD FE with the Tuners in a seperate BE. It works great. I run them on a gigabit switch that I picked up for $20 after rebate awhile back, but I doubt they would see any difference on a 100bT network. An hour of video is aprox. 5.7 gig on my system. Thats 1.583 MB per second. Assuming a 100mb network is going to see sustained bandwidth at 60% on average, that means it can sustain about 60mb/s or 7.5MB/s. (remember, 100mb is megabit, but we want to know it in megabytes)

By my math, I figure I could simultaneously run several HD frontends on an 100mb network. I've got gigabit though, so I am golden.

Next on my list is getting my Epia MII systems using their built in decoders to playback the HD content smoothly. I've read that it can be done with some experimental drivers. We'll see.

Thank you eveyone. I am now convinced that a hardware upgrade is calle for.

I do want to bring up a FE issue though. Last night, I watched two Episodes of CSI in HD format. In both instances, I was suprised how smooth they played compared to other shows that I recorded (PBS) while running on a 100 Mb/wired hub network. I still could not use FF or RWD, and playback paused in two instances for each show. Both shows would pause at the same scene when I replayed them. Two clicks of the FF button got the shows playing again.

This AM, I decided to mount /myth as an SMB share so that I would have access to my stored music, pictures, and video. Just before I left for work, I once again played one of the CSI episodes and playback was horrible. Pauses every two-three seconds at first, and voice was very choppy.

Could having a network mount effect things? Very strange.

I've got /myth as a smb mount and don't see those issues.

I'll also add, however, that I almost never use fast-forward or rewind in either SD or HD recordings, so I'm not aware of how playback is affected when using them. I always use 30-second skip or commercial skip: it takes a while for playback to stabilize when skipping through HD but it's not horrible.

I just registered today so, I might not be a help on the Knoppmyth questions. But to set the record straight, the part in BOLD that I have quoted from your post is incorrect.

The 400SC is a socket 478 P4 system. It doesn't do Dual Core. What you have (if you got the model number right) is a 2.4 Ghz 800FSB Hyper-Threaded CPU. There is a huge difference between the two (dual core and HT).

Based on what little I know about MythTV, it seems the 2.4 Ghz HT CPU also is enough HP for your backend needs unless a veteran on here corrects me.

You are most correct dvpatel. I accidentally switch HT with Dual-Core around. Correct, there is a HUGE difference.

Regardless, I'm going with the Dragon setup suggested in another thread. Can't wait, although I'm still shopping around for a ATX compatible case as my current Coolermaster only supports mATX.

I did want to post one last observation after having experienced HDTV for well over a week now.

If the recording isn't just sort of perfect, do any of you HDTV users experience pausing on your playback that can only be fixed with hitting the FF button? I'm thinking "recording integrity" may be another cause for the pausing I'm experiencing as I've repositioned my OTA antenna and managed to capture a few HD shows in near flawless quality and would only experience 1-2 pauses throught the show. Hoping moving to the AMD 3200+ would fix this.

Thanks!