Converting to AVI: best option for preserving sound quality?
 

I’m trying to write new AVI files for my portable media player (Cowon X7). The source files are DVD-compliant MPEG-2s, using the MPEG Layer II (mp2) audio format. I’ve tried writing one with avi.NET, which turned out very well except that it appears to only keep AC3 intact; otherwise, it compress down to MP3 with a maximum bitrate of 192 kbps.

This Cowon player has fantastic sound quality and I would really like to get the videos sounding as great as possible. Is there a recommended program that will write AVIs with flexibility on the audio output?

Cowon will support AVI or WMV, but I’d like to stick with AVI as it seems a more generic choice. However, should I consider WMV if there are no suitable options for AVI? Thanks in advance! :)

For the sake of accuracy, let's remember that an "AVI" is a wrapper, which mostly works to hide the actual video format. From a quick look at the device from the provided link, it appears to have been designed with Divx video format in mind. Divx commonly uses the AVI wrapper. Typically Divx is also encoded with MP3 or AC3 audio, and that's it.

MP3 @ 192kbps is "transparent" quality to a CD audio, the defacto standard upon which many digital audio compressions are based. And to be honest, 192kbps isn't bad. If you hear diminished quality, that's almost always a statement about the encoding hardware or software, and not an issue with MP3 or that particular bitrate (referring to 192kbps).

Honestly, you should not notice any real quality difference between a good AC3, good MP2 or good MP3. If anything, the wider dynamic range of AC3 can make it harder to hear on portable devices. Inversely, explosions and other loud sounds will be "rip the headphones off" loud. (Or more commonly, you'll quickly discover the point at which your small speakers or headphones will encounter audio distortion.)

For me, the biggest issue is deinterlacing. Are these commercial titles that you're sizing down for portable viewing? Or is this homemade videos that you're re-encoding. (Or course, some of this may be moot anyway, as portable devices have small screens anyway -- even the "big" 12-inch screens are so small that many flaws are hidden.

I would not consider WMV.

I'd use MainConcept Reference for MP4 (if supported), or I'd simply use VirtualDub for XVID encoding. If you want to go with dummy-friendly software, which has quirks and flaws, something like SUPER is easy to use. But again, not without its flaws.

I generally go from other>DVD, not DVD>other.

There are also a number of Chinese $30-range programs. Most of them are spammers, with crappy quality. One of the few exceptions may be Sothink, who doesn't spam to my knowledge. I won't give my recommendation (yet), but I would suggest looking at http://www.sothinkmedia.com/video-converter/
I've been asked to look at it, but have been putting it off. So busy. (Sothink makes some nifty web dev programs I've used.)

Avidemux is another one to look at. I've used it for some quick-and-dirty MPEG-2 encodes, but not tried the other way aroud. It's worth a test. I rather like it, to be honest, because of the included Vdub+Avisynth filters included. Not everything, but a nice mix of basics.

I'll look at that myself in a couple of days. Now you have me curious.

Okay, I ran a test. In Avidemux (freeware!), I opened the attached MPEG file (a Cartoon Network Smurfs promo), which was recorded from TV with either a DVD recorder or an MPEG capture card some many years ago.

It created an index of the MPEG right away; it asked for permission first.
Source file is 352x480 interlaced MPEG-2. Didn't look at the audio -- probably MP2 or AC3.

Then I changed the video setting to "MPEG-4 ASP (Xvid)" and left it at default settings (CQ:4). Feel free to tweak. And then changed it to "AC3 (Aften)" at 224kbps. It will re-encode audio and video to these new settings, with output to AVI. (File > Save > Save Video)

Attachment 1221

Because the VHS tape source was somewhat noisy for good compression, and had an overscan, and was a non-4:3 aspect, I ran a few video filters. Here's a screen cap of those settings:

Attachment 1220

Again, feel free to tweak for best NR, with balance of not removing too much detail. This was just a quick proof-of-concept test.

It's really quite easy to do what you want here. :)

Thanks guys. :)

I tried Avidemux and LordSmurf is right: a 320 kbps mp3 AVI sounds no different on my player than the 192. So I'm not even going to bother with this process. However, a 320 kbps music file (MP3) clearly sounds better on the Cowon than a 192. Weird.

Another thing that's bugging me about this player (perhaps this should be another thread?). It's a 160 GB HDD player, their answer to the iPod Classic. I initally tried the Classic and have discovered that both it and the Cowon's HD make a strange powering down noise. For lack of a better description, it will make a couple of very soft clicks and then will emit a short (and equally soft) "laser" sound, like a laser beam as it's dying down.

Both devices do this, brand new out of the box. A quick search online finds others having this issue with their Classics, with product exchanges producing the same results. Is this a quirk with how these kinds of hard drives are made? Have earlier Classics always been this way? Should I be concerned? It doesn't seem to affect either device in any way.

That's just a failing of its DAC -- not a failure of MP3 or the bitrate in general.

Again, you're simply seeing a failing of the device. A lot of items have quirks like this. CRT TV sets emit high pitched sounds. Hard drives can whine. Monitors can buzz. We used to have a TV set that "burped" (for lack of a better word) when powered on. Speakers can buzz or hiss.

I've heard this sort of intermittent high pitch sound on other devices, and those were hard drives, too. The issue here is mostly based on the fundamental of how drives must work, a byproduct sound of the mechanics. Good sound shielding would generally correct for this. Cheap devices have to skip something to lower costs, usually, and this may be it.

You also seemed to be burdened by good hearing. :)

Thanks LS, I figured that would be it. :)

I'm beginning to believe so, but I also make sure I have top notch peripherals (no weak links). The Cowon is brand new, but I already can't say enough about its sound quality. There are drawbacks - mostly with buggy software in need of a firmware update - but iPod users don't know what they're missing.

I've waited for years for a large capacity MP3 player with CD quality playback, and this is it. I just wish flash memory was up in the 100+ GB range already.