Tuesday, June 19, 2007

HDTV tuners

I think it would be worth having a separate post for the various HD-related items I'm researching to replace (or go in parallel with) my Comcast (now Time Warner) DCT2524/1612 cable box (reportedly has the same channel control signals as the DCT700). DCT-3416 (among others like SA 3250 HD (Version 2.1), SA8000HD (dual tuners?), DCT-5100 HD-Cable, etc) supposedly have working Firewire. Like always, AVS forum probably has others listed, and converter boxes. HDTVoice seems quite active as well. Might as well get one with digital (HDMI, display port, or DVI) output as well - plus dual tuners. What are the chances? Slim probably, the ones with dual tuners probably won't output dual to firewire or whatever.

Don't forget the small issue of cable card and other issues. Switched digital video is coming also. Supposedly "tuning resolvers" (or "tuning adapter") are on the way to help legacy and TIVO deal with that. Motorola has a MTR700 and Cisco/Scientific Atlanta STA1520.

This first section will be about HD tuners:
  • HDHomeRun appears to be an appealing option complete with MythTV support and QAM receiver... (i.e. dual?) typically $160 or $170.
  • The pcHD HD-5000 is also a good combo analog/digital HDTV receiver - and as a bonus, it doesn't support the broadcast flag. There are multiple people reporting poor receiver sensitivity though on this and the previous HD-3000.
  • DViCO Fusion HDTV5 USB (or PCI) has QAM and is inexpensive, well supported, and appears to work well. Reception/tuning might be better
  • Avermedia A180 / ATI HDTV Wonder / K-world 110 (or 115). Ebay for around $20.
The problem with the above, after finding a list of unencrypted digital channels, is that we'll be missing out on a BUNCH of channels if we don't go with a cable box, so it doesn't make sense to pay very many dollars for any of the above.

Semi-related: High def blog.

Until I get HD though, perhaps I want to stick with one of the Hauppauge PVR-x50 cards:
  • PVR-150 (super cheap and well supported)
  • PVR-500 (acts like two PVR-150's)
  • PVR-350 (has video out)
  • WinTV-PVR-USB2 (external tuner and conversion means less noise and slightly better pic quality). Drivers here.
  • I think I like the Plextor Convert X PX-TV402 since it has built in MPEG-4 encoding support
Compare the 150 and 350: here and here.

Update: I ended up getting the USB2 for now. Cheap and easy and works. Still need an additional cable tuner though, so that we can watch and record at the same time - and if I'm going to buy a tuner, it might as well have firewire output? Even better, I wonder if there are any dual-tuner cable boxes. AVSforum has a list of the various moto boxes. Here is another list. If I want to avoid firewire outputs, units to investigate include DCT2000 (designed to work with and external Motorola HDD-200 OR HDD-201 decoder), maybe DCT2244, DCT2524, DCP501, some 5200's, and some 6200 HD's. Supposedly the DCT2xxx series contain a 68k-based microcontroller. Time warner lists the manuals for the following DCT's: 2000, 2500, 5100, 6400, 6200, and 6208.

Super thread on DTCP/5C Firewire, and the CCI codes on the famous AVS forum.

Sunday, June 17, 2007

Copyright violation more serious than crimes against people?

Perhaps this explains why music companies insist on suing their own customers. Or why DVD's have stupid region coding schemes which prevents my Swedish speaking 5 year old daughter from playing the Swedish version of Pippi Longstockings in our DVD player purchased in Texas.

In short, they are completely out of touch with reality. I wonder how long they will stay this way, and how much damage they will do to American society in the process. I'm afraid of the answer. Would it be worth it to join a group that actively opposes them - perhaps EFF or EPIC?

Friday, June 08, 2007

Encoder and settings

When I go to reencode my music, the type and bit rate choices are huge:

While I don't anticipate using VC-1 a lot, I figured I should capture some baseline good settings that I've come across for encoding, just in case. But before that, why do I not anticipate using VC-1? Because H.264 seems to be somewhat more universal, and computing power is increasing quickly enough that I think very long term, I'd be sorry if I used anything except H.264.

Ben Waggner writes:
My general best practices for quality-emphasized encoding:
B-Frames 1
2-pass encoding, or Lookahead=16 for 1-pass encoding
Full Chroma Search
Adaptive Motion Match
Adaptive Motion Search Range

And you want to run in Complexity 4 (one less than the max).

Depending on the content, DQuant and Adaptive Deadzone can help a lot, especially with film sources
His blog also has screen shots of "good" settings and, more importantly, detailed explainations of what they do and why.

Encoding in Linux
Here is a step-by-step write-up of transcoding in Linux.
There also may be ways to decrease lag of a PVR device.

Thursday, June 07, 2007


If I'm intending on installing Linux, I suppose it would be worth it to collect up various links for things that I'm likely going to need to know.

For example, my US Robotics MAXg 802.11 PCI appears to be supported since it uses a BCM4318. But USB (which uses the BCM4320 / BCM2050) and cardbus are not yet supported (or maybe support is about there?) as of this writing (mid-2007). The USB is also identified as "Board: BCM94320R rev 3.1", which turns up a hit on google, but probably means it is based upon Broadcom's "AirForce One" reference design.

And then, of course, there are the free software drivers for the Intel graphics chipset, and various pieces of info floating around about it (like problems with video tearing). When something doesn't work, set the ModeDebug option in the xorg.conf file and post the config file and Xorg.0.log file. They also have a comprehensive developers guide on the X3000 chipset which probably would be good for their other chipsets as well.

And heaven forbid, if I ever have time to go into the kernal, here's a /. discussion of an article from IBM. IBM has a number of other possibly interesting articles.

I've seen mention that KDE integrates a lot of stuff better than GNOME, but that may not be true. There are two threads on ubuntu's forums about sizing the x-display as well - something a number of people seem to run into.

Musicmatch for Linux? Many people swear by amarok (with Sound Juicer or GRIP for ripping) - but it is KDE. Exaile is a GNOME version of that, with a ripper plugin: sudo apt-get install exaile Rhythmbox is quite popular as well, and Banshee is supposedly a cross between the two: sudo apt-get install banshee banshee-official-plugins (although some still prefer Exaile). There's another app called listen.

The big question is why Mythmusic isn't listed here.

Cool tips and tricks:
  • Some (AOL, of all companies) allow you to remotely mount free filesystem space by doing
    sshfs userid@members.aol.com: /some/directory
For a mail server investigate: maildirs (with "-T news" preset). On the topic of mail server(s), ePOST looks very interesting... encrypted and p2p for redundancy.

Here are some configuration items related to optimizing a Linux system for MythTV. For example, using RAID and one big file system to record multiple shows can result in massive fragmentation (is Storage Groups the answer?... or allocsize + running xfs_fsr at night. Also studies show that you need to keep at least x% free [5% on a 250G hd])? Is threaded writing the cause for the fragmentation? Speaking of which, the consensus appears to be that affordable RAID is best done via software. Hardware RAID, done right, is mighty expensive (starts at $250 and jumps to $400 and more very quickly). Ultra-320 SCSI array may actually still be worthwhile as well?! "Whatever you do, put a pair of hot-swap drive bays in your server" (which might mean using at least SATA 2.5). This guy did some interesting splits on his drives.

Restoring RAID:
Rebuilding the partition table is very easy.

sfdisk -d /dev/sda | sfdisk /dev/sdb (sda = good_disk, sdb = new_disk)
raidhotadd /dev/mdX /dev/sdX

Speaking of RAID, need to read and keep in mind that read errors are becoming more common as disks get larger.

Other interesting performance params: stripe_cache_size? Using 64 kByte block sizes. More complete list on this ubuntu-mythtv thread.

xfs (maybe with -o nobarrier and other tweaks for performance like noatime,nodiratime,logbufs=8,allocsize=512m) or reiserfs (version 4 or newer) are supposedly better file systems to use than ext3 for large file reasons. There seems to be differing opinions on LVM possibly causing problems, yet plenty of people use and love it, although with cavets (don't put more than one physical volume [PV] in an LV... PV's failing is not pretty). Check here on how to use pvresize to resize PV's. Installing LVM on Mythbuntu is outlined on the forums. I ended up doing and LVM over a RAID over xfs. Here's some step-by-step lvm manipulation.

Or ZFS with RaidZ2 support? ZFS has changed peoples lives? Except ZFS is only available as a (slow) userspace filesystem on Linux right now.

1TB drives are too expensive for me to be able to justify right now (~$260 for non-RAID, $100 or $150 more for RAID), so that means I'm going to have to go with smaller drives and grow/migrate the RAID later to a larger OR bigger drive, presumably using mdadm OR gparted. There is also something called resize2fs, and of course fdisk.

While on the topic of drives, backups and be live (snapshot), or not. And we need to secure the box, including mythweb and samba in particular.

Speaking of MythTV, I have another posting which is a random collection of lots of stuff... here I will collect more specific things.
  • Here's a discussion of light-weight window managers. blackbox/fluxbox appears to win his support.
  • Here's step-by-step for mini-myth on a thumb drive.
For sync'ing machines / offline files, rsync is the way to go. Here is a discussion.
Ubuntu Upgrades:
  • sudo aptitude install update-manager-core; sudo do-release-upgrade
  • -or-
  • update-manager to do it graphically
Linux driver guys live here. If I'm thinking about upgrading/hacking my own patches for the kernal, start at Kernal Newbie and "how to compile a kernel". There's also a forum thread and another blog entry. Looks like it might be a one step process now with kcheck, although it is perhaps not as optimized as it could be (at least, without manually changing a file?). USB driver info on the LinuxTV wiki. There's also a Custom Kernel build page on the ubuntu site.

More interesting stuff related to the Linux Kernel:
New topic: sound... specifically, remote sound. EsounD is one option (perhaps outdated). Polypaudio now? Looks like a long-standing topic.

New topic: Install/package stupidity. Ubuntu has dpkg, apt-get, synoptic, and aptitude. Each does something in a little different way. Some are more powerful than others. Graphical ones don't give you good error handling (check disk space before trying to install a kernal - or at least tell you what went wrong?). Avoid them and use the command line.

sudo dpkg-reconfigure mythweb
sudo aptitude reinstall mythweb

To reinstall, it's helpful to have a list of the installed packages.
dpkg --get-selections | grep -v deinstall > ubuntu-files (picks up purge pkgs)
dpkg –-get-selections | grep "\binstall" > ubuntu-files

then later:

sudo apt-get update
sudo apt-get dist-upgrade
dpkg --set-selections <> /home/user/location_on_remote/ubuntu-files

placed in /home/user/.local/bin, named package_list.sh and made executable.

"apt-get clean". Also try "apt-get -f update" to completely any unfinished business. apt-get install -f worth remembering as well. Then there is dpkg, and a summary of it along with apt-get.

aptitude seems more consistent than apt-get. More comparisons. aptitude has easier to read logs (in /var/log)