JHauge's blog

Philosophy major turned web developer

25 Jan 2012

Sony Bravia TVs and high quality jpgs

I recently bought a brand spanking new Sony KDL-40HX723 Bravia TV. This TV has en ethernet connection, it’s DLNA compatible and has enough multimedia functions to make me fairly sure I won’t need a Media Center PC attached to it.

One of the things I was looking most forward to was browsing the pictures we’ve stored on our local Synology disk station, that functions as a media server for our pictures, home videos and music. But no such luck.

The problem

Every time I tried viewing a picture i could see in the list the TV gave me a “Unable to show file” message, instead of the full HD large size goodness I’d been looking forward to, which of course left me a little miffed.

The problem went away if I changed the “Browsing Settings” on the Synology NAS to “Transmit low resolution images instead of the original images.” Which led me to believe the problem had something to do with the size and quality of the images stored on the server.

I shoot almost all of my pictures in RAW format, and edit these in Adobe Lightroom, from where I export to the Synology server in JPG format. So I started doing some test where I tweaked the output settings, but all my attempts failed.

So after some extensive Ducking/Googling with DuckDuckGo I finally found this blogpost that put me on the right track.

As Wouter Horré states Bravia TVs support the DCF 2.0 standard, which as is stated in the DCF 2.0 specifikation only supports Pixel/Chroma Subsampling YCbCr 4:2:2 or 4:2:0. This means that compression of the colors in the pictures is done in blocks of 2px across.

But professional image editors like Adobe Lightroom, Adobe Photoshop and probably others use yCbCr 4:4:4 subsampling to increase the quality of the images. Sony Bravia TVs doesn’t play nice with this setting.

The solution

I took Wouters lead and downloaded the excellent ImageMagick tools for Windows. This tool collection has a tool called Mogrify which is a command line based tool that can do all sorts of things to image files.

After this was done I could probably have installed the LR/Mogrify plugin, and plug mogrify into the export process In LightRoom, but the prospect of exporting 7 years of digital image files once more didn’t have much appeal to me. So I whipped out a text editor and appended the following little powershell function to my profile.ps1 file.

function global:ConvertTo-Bravia {

    Get-ChildItem $path | ForEach { 
        &'c:\Program Files\ImageMagick-6.7.4-Q16\mogrify.exe' -sampling-factor 2x1 $_.FullName
        write "Converted $_"

This means that when I open up a my Powershell command prompt I can change the chroma subsampling method in all the files of a given directory by just typing ConvertTo-Bravia .\MyPictureFolder, and then kick back and watch while my computer happily chucks away on the files in the directory.

Or just sit back and watch the pictures I’ve already converted on my brand spanking new Sony TV, that doesn’t like high quality jpg images. All though I’ll admit I probably wouldn’t be able to tell the difference between the two subsampling methods sitting 10 feet away from the screen.