Review of the Panasonic Viera TX-40DX700B

This Panasonic TX-40DX700B is a 4K and HDR 40" TV.

• I agree with many of the reviews that this TV has an excellent picture both for DVB broadcasts and content received over the Internet such as Amazon video. 4K content, although limited at the moment, looks great
• Despite being 89.5 cm in width, the arrangement of the legs usefully enables the TV to be placed on a stand which is not so wide. It will actually fit on an 80cm stand (just) although I'd advise a slightly wider stand. To note the legs cannot be moved towards the centre of the 40" TV, unlike the larger models.  
• The TV worked fine at the outset then it became impossible to access any live broadcasts. Pulling out the plug to reset the TV resolved this. This issue hasn't reoccurred
• The TV incorporates a DLNA client in order to render content stored on a DLNA server. Bear in mind that the media server must be DLNA-compliant not just UPNP-compliant. DLNA is fussier than UPNP but I find the DLNA client on this TV reasonably flexible in terms of playing media formats (obviously not as flexible as media player like mplayer). However, see below regarding photos 
• Some observations about DLNA servers
• For users of the open source DVR Mythtv, the DLNA client on the TV is compatible with v.0.28 of Mythtv. As a DLNA server, mythtv is useful for browsing and showing TV recordings. However if you want to watch videos, they are all grouped into one directory which not very useful if you have them grouped into sub-directories
•  The TV also works well with minidlna which is good for browsing directories of videos as (unlike mythtv) the directory structure is preserved 
• The media browser includes a slideshow option for photos. This is surprisingly basic since there are no transitions between the photos (such as crossfade) and the music (if selected) is pretty dire. Only JPEGs are supported and I also found a JPEG edited and exported back to JPEG in Gimp would not display ("File not supported", but a further conversion to JPEG in ImageMagick resolves this issue. kodi, which i have running on a Raspberry pi 2 connected to the TV is much better: you can run music in the background, kodi uses decent transitions and Kodi will play a range of image formats
• The Apps interface is slick but the selection of apps quite limited compared with an Android TV (judging by the reviews). Personally I prioritised the picture quality and screen size over the Smart TV functionality

Panasonic Viera TX-40DX700B as a DLNA client rendering content from a Mythtv UPNP server

The Panasonic TX-40DX700B is a 40" 4K/HDR LED smart TV  which includes a DLNA client.

This blog describes a configuration which includes the TV as a renderer and a Raspberry Pi 2 running a UPNP/DLNA media server.

Having received the Panasonic TV, the aim was to replace an HTPC sitting under our old TV with something more minimal while retaining the ability to record programmes using Mythtv and stream them to the TV. While this works well, it  is probably a temporary configuration because an HTPC with mythtv's full functionality provides much greater flexibility than a Smart TV with DLNA.

The TV tuner is a PCTV 290e HD USB tuner which is supported in the Linux kernel. This is connected to a Raspberry Pi 2 running a mythtv backend (v.0.28). Raspbian  Jessie is installed on the Pi 2.

Jessie includes mythtv-light which provides the frontend for mythtv. There are instructions here on how to install and configure it. Debian Jessie does not include the packages for the mythtv backend. It is necessary to add a backports repository to /etc/apt/sources.list e.g.:

deb http://ftp.debian.org/debian jessie-backports main

A useful way to sort out the dependencies for the mythtv backend on the Pi2 is to install Synaptic and then install these run-time dependencies (as described here):

mysql-server-5.6 ntp libicu55 libqt5sql5-mysql mysql-client-5.6

I assume that most if not all the other dependencies for the backend must have been installed by the mythtv-light package. I couldn't find libicu55 in backports and libicu52 is running on the backend. I have not yet had any issues using this earlier version of libicu.

The Pi 2 has to be overlocked in raspi-config in order to receive HD television broadcasts via the PCTV tuner otherwise fast-moving video will be pixellated.

In this configuration, TV broadcasts are stored on a remote PC running Gentoo and a Mythtv frontend. Having installed a mythtv backend on the Pi 2, it automatically runs a UPNP server. As noted in the v.028 release notes DLNA compliance is improved in this version of Mythtv.

The Mythtv DLNA server can be accessed via the Devices menu on the Panasonic TX-40DX700B. The Mythtv UPNP server displays the friendly file name and includes menus by channel, recording time etc. A minidlna server is more convenient for videos if you have them arranged in folders because minidlna preserves the folder list whereas Mythtv displays all videos in a single list.

I am not transcoding any of the recordings on Mythtv and it is useful that the Panasonic TV can handle Mythtv's native recording format. Many but not all videos stored in my Mythtv videos directory also played on the TV with navigation including videos in .avi, .mpg and .mp4 format. As expected, not everything was compatible with the TV's DLNA client and some transcoding will be necessary.

For users of Mythtv, my recommendation would (if possible) be to retain the use of the Mythtv frontend rather than to rely entirely on a smart TV. Mythtv accepts a huge range of formats and I find the menus a bit less clunky than the DLNA interface. However there is additional cost involved in having two video renderers feeding the same display device. The costs could be kept to a minimum by using a single board computer for the frontend, perhaps dedicated to it. In my experience, the Pi isn't powerful enough to run a frontend and backend at the same time although it does an amazing job of running the backend which I can access and configure remotely. It is also possible to standard definition  live TV on the remote frontend, HD is a bit laggy using this configuration. I have yet to try the Pi 3but this is an obvious candidate for a  mythtv frontend or backend.

HP Envy 7640 printer under Linux: review and tips

This printer works well under Linux.

I found that the HP Linux Imaging and Printing (HPLIP) didn't find the printer automatically but with an Ethernet connection it was only necessary to tell HPLIP the internet address. The printer/scanner was then ready to use.

The printer requires a properly configured Ethernet connection if you are using a wired network setup. Otherwise the printer might not wake up from sleep mode even if you press the front panel to activate it. For some reason I found that a connection through a switch to a router caused this issue but a direct connection to the router was fine.

Xsane works well, in addition to flatbed scanning you can carry out multipage scanning using the document feeder.

There is a useful, configurable HP Web interface to the printer with options to scan, configure settings, view usage statistics etc. Sometimes, but not always, I find that accessing the Web interface causes the HPLIP interface to freeze, and you have to close down the Web interface to access the HPLIP interface again. I also found that Firefox displayed blank PDF pages after scanning via the Web interface. A message is displayed: "This PDF document might not be displayed correctly". Clicking on the Firefox button  Open with a different viewer and then choosing Evince resolved this for me.

Certain actions like aligning the printer and cleaning the cartridges can't apparently be carried out by using HPLIP or the Web interface, you have to
use the front panel of the printer.





        

Amazon video under Linux

Amazon video now works great under Linux. Once Amazon had rolled out an HMTL5 player it was no longer necessary to spend time on workarounds because there was no Linux version of Silverlight. Of course Google Chrome is a necessity, other browsers can't be used.

There seems to be a compatibility issue with running the Amazon player under Gnome 3, a distracting white border appears down the right hand side of the screen and along the bottom. Using a window manager (like the excellent Openbox) solves this.

Another quirk is that the mouse pointer doesn't disappear automatically when using a window manager. Right clicking solves this although you have to wait for the player overlay ("Options", volume control etc.) to fade out.  

Automount a USB media player in Linux

It is useful to be able to automount USB file systems when the USB device is plugged into your computer.

This is an example of automounting an mp3 player (Creative Zen xfi) running Rockbox in a Gentoo system.

I did this in 2 stages.

Since the device name of the mp3 player will vary (could be /dev/sdd1 /dev/sdf1 etc.) the first stage is to ensure the device name is always the same. This is a useful site with good examples of how to do this.  I created a file as shown on this site called /etc/udev/rules.d/65-stick.rules containing:

# # Rockbox device
KERNEL=="sd*", SUBSYSTEMS=="usb", ENV{ID_VENDOR}=="Rockbox", \ ENV{ID_SERIAL}=="Rockbox_Internal_Storage*", SYMLINK+="zen%n", GOTO="stick_end"
LABEL="stick_end"

This rule uses unique information about the device which you can gather through a couple of commands. First, dmesg, which in this case allows you to identify the device name. Here is an extract from the dmesg output:

[1203747.956962] usb 4-1: New USB device found, idVendor=041e, idProduct=4162
[1203747.956965] usb 4-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[1203747.956967] usb 4-1: Product: Rockbox media player
[1203747.956969] usb 4-1: Manufacturer: Rockbox.org
[...]
[1203748.988809] sd 243:0:0:1: [sdf] 31291392 512-byte logical blocks: (16.0 GB/14.9 GiB)
[1203748.992059] sd 243:0:0:0: [sdb] Write Protect is off
[1203748.992064] sd 243:0:0:0: [sdb] Mode Sense: 0b 00 00 08
[1203748.994794] sd 243:0:0:1: [sdf] Write Protect is off
[...]
[1203749.040790]  sdb: sdb1
[1203749.047790]  sdf: sdf1
[1203749.088771] sd 243:0:0:0: [sdb] Attached SCSI removable disk
[1203749.091768] sd 243:0:0:1: [sdf] Attached SCSI removable disk

From this I can tell that the device's internal drive is /dev/sdb1 and that the SD memory card in the device's memory slot is /dev/sdf1.

The command udevadm info /dev/sdb1 shows some further information about the device including the following lines: 

The ID_SERIAL and ID_VENDOR values are now used to uniquely identify the device in the udev rule shown above. 

The udev rule ensures that symoblic links is created for the Creative Zen device. The device names are always  zen and zen1.

The following command ensures that any new udev dule is active:

udevadm control --reload-rules

Now to autofs for which I found this Gentoo wiki page the most useful. I emerged autofs and then ensured it was enabled and started in systemd:

systemctl enable autofs.service

systemctl start autofs.service

Next I edited the /etc/autofs/auto.master file to include:

/media   /etc/autofs/auto.misc    --timeout=15 --ghost 

This means that the mount instructions in auto.misc will mean that the filesystem is mounted under /media.

My /etc/auto.misc has the following line:

zen          -fstype=vfat,rw,uid=1000,gid=100          :/dev/zen1

 This means that a mountpoint /media/zen will be created for the device /dev/zen1 and that the filesystem is writeable by the user. 

Musescore 2.0 on Gentoo

Good to find out today that the development version of version 2.0 of Musescore compiles successfully on Gentoo using the instructions on this page.

I need to keep Qt4 on my system as it is quite old so I installed Qt5 into my home directory and set the path for Qt as described in the compile instructions. The nightly build I used from Git was 10 January. I followed the instructions to build a binary called mscore-self.

So far the new version has run without any issues and the new default soundfont is great, it transforms the playback of scores.    

Building the Polyphone soundfont editor on a Gentoo system

Polyphone is very useful soundfont editor. Version 1.7 compiled without any issues on my Gentoo system once I had edited the polyphone.pro file (one of the source files) and uncommented these lines (taking the initial hash out):

#DEFINES += USE_LOCAL_RTMIDI
#DEFINES += USE_LOCAL_STK
#DEFINES += USE_LOCAL_QCUSTOMPLOT

This stops qmake trying to find the relevant files in your main Gentoo library directories. As it says in the polyphone.pro file:

# Uncomment a line if your distribution doesn't come with some of the following libraries

It is possible to emerge rtmidi (one of the dependencies) from the Gentoo lorelei overlay but Polyphone's installation script still won't find it.

Using the process described here, you end up with a Polyphone binary which works fine.

The version of GCC used was i686-pc-linux-gnu-4.9.3.