AVCHD (.mts) to XviD (.avi) - Terrible quality problem

[octogon]

I hope you guys can help me with the following problem.

I have a
- .mts file
- using AVCHD compression
- with a resolution of 1280x720
- with a bitrate of 10 Mbps
(taken with my JVC GZ-HM30 HD camcorder)

which I need to convert into an
- .avi file
- using XviD compression
- with a resolution of about 640x360
- with a bitrate of about 1000 kbps

I'm using Sony Vegas Pro 10.0.

When I convert it into the desired format, using the desired compression, quality of the picture is just terrible - pixelated with an obvious "pixel motion".

I'm wondering what am I doing wrong?

Is the target bitrate too low?
If that's the case, then how come video converted from other high quality sources like DVD turns OK when converted into XviD with a bitrate of around 1000 kbps? I've tried converting the video into XviD with bitrate up to 4000-5000 and only then is the video quality acceptible.
In other words, am I to have no other option other than using much higher XviD bitrate (4000-5000) on the expense of file size?

Do I need to use temporary uncompressed (or some other) format?
Do I have to convert the video into an uncompressed format first and then into the desired one? If so, what would be the most suitable temporary format in this case?

My ultimate goal is to achieve quality of video as in the case of converting DVD quality into XviD (with a bitrate of around 1000 kbps).

MP4/h.264 is out of the game because I need the converted home videos to be able to play on a standard DVD (XviD) player.

I hope I managed to describe the problem as straightforward as I can.


Thanks in advance!

[yoda313]

Well you shouldn't get "terrible" quality but you are downconverting from hd to sd. There is going to be quality loss no matter what you do. But like with most things the tolerance is different from person to person. What looks ok to somebody looks terrible to somebody else.

I need the converted home videos to be able to play on a standard DVD (XviD) player.

You will be limited to sd all day everyday in this fashion.

If you are going to somebody elses home can you bring the camera with you? Than you could playback the original file on the camera hooked up to the tv (assuming its an hdtv and the camera has component or hdmi out). No conversion will be necessary.

To keep it in hd you could make an avchd if they have a bluray player or ps3. That is high def on a dvd disc. But it is only playable on a bluray player or computer.

If you have a settop media player like a wdtv media player you can use that to play the original file from a harddrive. You take both with you to show it.

Another option would be to upload it to youtube and set it to a private channel. Than you could watch it online at the other persons home assuming they have a fast enough internet connection. Of course you have to be careful because youtube might not do the best job with the video on the upload - though I have seen decent hd video on youtube (again in the eye of the beholder stuff it might look horrible to other people but you can do 720p video on youtube).

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If you must do the file conversion to xvid/divx do understand the limitation of standard definition resolution. There will be quality loss from the conversion. It shouldn't be horrible though.

Unfortunately you should test it out yourself as you are the one who will be the final judge in the matter.

Simple observation is obvious that the higher the bitrate is in general the better the final file will be (relative to the same file at a lower bitrate). There is a point of diminishing returns when extra bitrate doesn't do anything to the video. You will have to find that sweet spot yourself on your own material. There is no real scientific perfect answer for what bitrate to use. Edit - however a bitrate calculator will at least tell you what the file size will be when you are picking your settings.

Use dual layer discs to get more space and check to see if the dvd divx player can read from a harddrive. However chances are it will only be a fat32 harddrive and hence a 4gb file limit - however if its a particularly older model it might have a 2gb divx file limit regardless of what form it is played back from.

Oh and make sure to use a powered harddrive if you use either a media player like a wdtv or attach it to a dvd player.

Also note many bluray players can playback video files from a harddrive or on disc and tvs can too if they are a "smart" tv - or some models before the "smart" term was coined a few years back.


Edit - after reading your post again you mention a motion issue. Could you have manipulated the frame rate by mistake? It should be the same as the source. If this was 720p you should downconvert to a progressive format and don't mess with the fps either.

[manono]

Is the target bitrate too low?
If that's the case, then how come video converted from other high quality sources like DVD turns OK when converted into XviD with a bitrate of around 1000 kbps? I've tried converting the video into XviD with bitrate up to 4000-5000 and only then is the video quality acceptible.
In other words, am I to have no other option other than using much higher XviD bitrate (4000-5000) on the expense of file size?

Try something - reencode your XviD as a 1-pass encode for quant 3. Does that look OK? Is the size much larger than yours with the 1000 bitrate? Maybe the equivalent size to the ones you did using 4-5000 bitrate?

You're comparing apples to oranges when comparing home-made movies with professionally created Hollywood movies. Different sources compress differently. Yours, apparently, don't compress worth a damn. Overlit? Too much movement? No tripod? Lots of noise in your videos from using inferior equipment? There could be all kinds of reasons.