[Touch HD General] Chris Cross:
A basic intro to video conversion

Yeah - :D

Glad to hear it got solved.

And now in terms of the video thing, here is a basic introduction.

PLEASE SEE UPDATED VERSION OF THIS POST IN THE WIKI

Keep in mind I am absolutely no expert - and so the video experts here might cringe at my explanation. :p So if any of you experts out there want to correct me - PLEASE DO - I always like learning new things.

Okay, different things affect how your HD will play a video. The more the processor is pushed to its limits the poorer the quality you will see when playing a video. So, the trick is to find a happy medium between some of the main contributers to quality and processor drain.

1. The bitrate (kbps) is a measure for how much data information is being processed per second. The higher this number, the better the picture, but it also means the processor needs to work harder.

2. The resolution (or scale size) refers to the number of pixels (width x height) that the video will be shown in (at a natural 100% zoom). The higher the resolution, the clearer the picture - but also more work for the HD.

3. The frames per second (fps): A video is basically made up of a bunch of individual frames (or pictures) that are played really fast one after the other. You will often see settings between 23 and 30 fps. I have to say that I don't really see much difference here. However, sometimes if the audio is not properly synchronized with the video after you have done the conversion, they recommend you check what the fps of the original video was, and then keep it the same on your settings for conversion.

4. The aspect ratio is basically the shape the video will be in. 3:4 is your standard TV type size, while 16:9 or 16:10 are common wide screen formats. I personally like the wide screen formats. There are other aspect ratios, but these are the really common ones. Ideally you want an aspect ratio that will be as close as possible to the aspect ratio of the monitor or screen that you will be viewing the video it. That way it just fits nicer. :)

5. And finally the audio encoding. It also has different settings. Basically four things:

Type of encoding (for example mp3, AC3 or AAC etc.)

Bitrate (kbps - same concept as in video bitrate): Common is around 128kbps

Sampling frequency (in Herz: Hz): Common is 44100 Hz

Mono (1 channel) vs. Stereo (2 channels) sound. There is also 6-channels for surround sound, but that won't do much on your HD.

So, there you have the main things that you should be familiar with. And now, all those settings can be packaged up in different ways. That brings us to the OUTPUT settings for conversion. The goal is to achieve the smallest possible file size with the best possible video quality.

You can look at it as a container that holds a specific formula or encoding inside. Container formats are, for example, .avi, .mp4 and many others. However, the "formula" inside these containers can vary a lot. That is the "encoding" or "codec". Some examples are divx, xvid, MPEG-4, .h263, .h264 etc. So, two different videos might both have file names ending in .avi (the container), but have a totally different encoding inside that container. One might be an xvid and the other one an MPEG-4 - or whatever.

If you use SUPER to convert videos, you see how it is nicely broken up into the different categories for you to choose settings. See the picture I attached. You can either play with different settings, or you can use settings that other people have posted and said they worked well for them.

The HD is limited as to what it can play. So depending on the container and codec used, you can use the HD's album program to play the video or you might need third-party programs like CorePlayer (for example to play divx). The thread I posted earlier shows what different people have tried and how their experience was when using the HD's native album player, or the HD's Windows Media Player or third-party software like CorePlayer.

There is one more thing... called "hardware acceleration". It is a technology that greatly improves how smooth a video is, especially in fast scenes with lots of movement. It involves a piece of hardware (hardware accelerator - like a graphics card) as opposed to just the software. The HD is equipped with this technology, and so its native player can use it. However, programs like CorePlayer don't support the use of a hardware accelerator yet - but CorePlayer has the advantage of being able to play codecs (like divx) that the HD alone cannot play. It's all a give-and-take trying to see what works best.

I tried several players and ended up staying with the HD's native album player with its hardware acceleration. But to get the best quality I end up having to convert most of my videos, and that can be quite time consuming. Everyone has different opinions on that. Some people love CorePlayer.

Sooo, I hope this basic introduction helps you understand other threads a bit better. If you have questions - just ask. I'm not an expert in this, but other people here are pretty knowledgeable when it comes to that.

Cheers