Mobility and media

As a birthday present to my self I recently bought an Archos PMA400. I have to say that this device is very nice and while not my idea of the perfect mobile device, which in my opinion should basically have the full computing power of a server, wireless, digital telephony connections, and long battery life, its not far from it. Aside from being a standard PDA which runs Linux, it has a number of other features including being able to plug into a TV and record any channel and play it back either on the TV or its own screen. While that type of functionality is not unique, especially as the recent trend towards PVRs continues, what is unique is how user friendly and convenient Archos has made it. My pma comes with a cradle that you plug it in and then plug the cables (scart for the euros) into the relevant parts of the TV. Now when you plug it into the cradle it enables an infrared receiver on the cradle and the included full, normal remote control now controls your pma. Even better then that the PMA learns the signals that activate your TV / stereo etc and now you can control ALL the devices via the PMA which sits there and relays stuff back to the relevant device via IR. Battery life, while not as good as I would ideally want it, is enough to play music for 9 hours and videos for 4.5 hours. All in all its fairly amazing and because it runs linux I can support ANY codec I want, including DRM'd if I was so inclined (I'm not) through to the more windows centric and of course all the open source ones. If any of you reading this have any familiarity with OpenPMA then let me know because I think that is the firmware I will try running on it next. So I've got my media player now what?

For a long time I've been uncertain about what to do with the digitalization of media. As a technologist I think its great, I mean its so much easier to list, select and play digital songs / movies then having to swap physical media around. The problem I have is that I'm very particular about the quality of both movies and music as I have spent a small fortune on a good home cinema and I can hear the difference between a 128kb mp3 encoded song and a 192kb one. The obvious solution is to just store everything in a lossless format (that is in its pure unaltered form from the cd / dvd), however, the concern about that is the amount of space that would require. Here the nice thing is, that having procrastinated so long, the amount of storage required, while once infeasible, is now very very affordable. So I decided that I would store all my media in a lossless format and then transcode on the fly any time I wanted to put it onto a more mobile device, like my Archos PMA. I set out to do some research on codecs and media.

The first thing that I discovered was that WAV format, which I had mistakenly thought was a raw music format is actually in fact more of a general container and not specifically for music. As a result of this there are a lot of extra things in a .wav file then you would need for encoding pure music for example. Looking into it further I discovered that FLAC was generally regarded as the best lossless format, the reasons being that it compresses up to 2/3 more then original WAV format, it can be streamed, tagged is completely open source and widely supported for a lossless format. After my investigations I have decided that I will store all my music in FLAC and then transcode them into AAC format for listening on portable devices or where space is an issue, AAC having been chosen after I conducted a number of double blind listening tests to see what my ears prefer. Now it was on to movies.

Storing movies is a lot more problematic then storing music. For starters there is two aspects to any movie, the picture and the sound, and while playing back picture is relatively straightforward, playing back sound can be very complex. The main problem with the sound for my requirements is that often the mechanism that is playing the pictures wants to also process the sound, in my case a computer. The issue with that is that no computer, regardless of how good a sound card, can run my speakers at the necessary requirements as well as my amplifier. This was causing me a lot of problems initially until I realised that I could keep the sound and just allow the mechanism that is playing the pictures to "pass through" the sound to another external decoder, in my case my aplifier. The question then was what was a satisfactory quality?

The question of quality I decided was moot in the end because I will do a similar thing with my movies as I have done with my music, that is I will just keep the full dvd image and when I want to watch the movie on another device I will just transcode it to something else. Now the question is what is the best something else? After doing some research it seems that Divx5 is generally regarded as the best picture codec, however, xvid4 is not far behind. Xvid (divx backwards) is an opensource codec that started off a fair way behind the current codecs at the time but up until the recent release of divx5 was leading the way. Even now, while many think that divx5 is better then the current incarnation of xvid, there are some areas which it would appear to be better, and as a believer in open source I strongly suspect that xvid will shortly regain its crown as the leading codec. Because I support open source and xvid is very widely supported, I will encode all my movies to xvid for use on mobile devices.

So there you have it. My advice to people considering moving their collection of music and movies to pure digital formats is to go out and buy a cheapish SATA raid card and 4 x 300gig hd's. This means that you will about 1 TB of storage which will be more then enough for most peoples entire cd and dvd collection. Store the cd's in FLAC format and the dvd's in a raw image and transcode them into AAC or xvid if you need to play them on more mobile devices.