Beta5 #5-Conversion to Video choice....

[goddi]

Greetings,

I was trying out the Custom conversion to AVI video method in the latest Beta. I have been using it in the 4.48 version but I see there are a few different choices to make and some have remained the same.

My first question has to do with the choice of Codec. In my experiments, I have found that the 'DivX Mpeg4-Fast Motion' seems to be the best choice and delivers a useable AVI file. (However, it is not as good as what is produced using the PTE Codec and buring it directly to a DVD). So my question here is, is this the best Codec to use when using the Custom choice?

When using the Custom method, I have gone into the Configure menu and made changes to the Datarate, and other choices. But when it is played, those items do not seem to stick. The datarates stay the same as the defaults settings and the quality does not seem to change. Should these have any affect on the final quality??? If so, how do you decide what the changes to these setting should be???

I am making these Custom AVIs so I can post them on sites like Google Video, etc. The quality does not come out real great but it is another option to use. If anyone has any hints on using the Custom method to get the best quality, I'd appreciate any help.

Thanks... Gary

[Lin Evans]

Greetings,

I was trying out the Custom conversion to AVI video method in the latest Beta. I have been using it in the 4.48 version but I see there are a few different choices to make and some have remained the same.

My first question has to do with the choice of Codec. In my experiments, I have found that the 'DivX Mpeg4-Fast Motion' seems to be the best choice and delivers a useable AVI file. (However, it is not as good as what is produced using the PTE Codec and buring it directly to a DVD). So my question here is, is this the best Codec to use when using the Custom choice?

When using the Custom method, I have gone into the Configure menu and made changes to the Datarate, and other choices. But when it is played, those items do not seem to stick. The datarates stay the same as the defaults settings and the quality does not seem to change. Should these have any affect on the final quality??? If so, how do you decide what the changes to these setting should be???

I am making these Custom AVIs so I can post them on sites like Google Video, etc. The quality does not come out real great but it is another option to use. If anyone has any hints on using the Custom method to get the best quality, I'd appreciate any help.

Thanks... Gary

Hi Gary,

Let's start with the second part of your question. Yes, the data rate and other issues do make a difference, especially when the AVI is played back at higher resolutions and not over the web. The settings that affect image quality are: Frame rate (the number of frames captures per unit of time - usually per second). Whether "progressive" or "interlaced." The interlaced mode is designed to accommodate broadcast television where the image is created by tracing one scan "line" at a time and skipping every other line on the first pass then returning to "fill in" the missing lines on the second pass. For example, in the United States, the NTSC standard calls for 525 lines and 60 cycles (Hz) per second. This means that lines 1, 3, 5, 7, 9, etc., are traced from left to right (as you view screen) then when line 525 has been traced the electron beam quickly sweeps back to the beginning and traces lines 2, 4, 6, 8, 10, etc. The persistence of the phosphor triads when excited by the electron stream from the CRT is long enough that we see minimal flicker so this "interlaced" method works pretty well. But on a high quality LCD or CRT on a computer, the "progressive" mode (lines 1, 2, 3, 4, 5, 6, 7, etc.) trace produces a cleaner image with less flicker and is preferred.

I'm not sure why you are not seeing some difference in the playback when choosing different parameters, you definitely "should" see differences. Codecs (compress/decompress) algorithms resident on your computer account for different choices on the "Create Custom AVI" menu. There are numerous codecs and whenever you install new software you may be adding to the list. You can also download free codec "packs" such as the "ACE Mega Codecs Pack" where you can install as many as you wish.

As far as which are "best" - the answer varies according to your intended use. Some codecs compress more than others so are preferred when trying to minimize file size for the web, etc., Some compress very little and for playing on a computer, compression isn't a big issue. Generally, the Microsoft MPEG 4 video codec is considered one of the "better" for image quality, but the DivX Pro codec is also quite good and has many, many quality "settings".

The purpose for having different data rates, bitrates, etc., is to facilitate being able to play the files over a limited bandwidth medium such as the web. If the datarate exceeds the ability of the connection to feed the data to the computer via the web, then the show will stall, start, stop, etc. Those with broadband may be able to play fairly high datarate shows, but dial-up connections will be overwhelmed. For playback directly from a hard disk, CD or DVD on a computer, fast datarates are fine and there is no sacrifice in image or audio quality by choosing even an uncompressed mode.

When you post you shows on the web, whether AVI, MPEG I/II or Flash, you must use a fairly low bitrate so as not to overwhelm either the storage capacity or load time or cause the viewer to have to wait for lengthy periods as the show downloads. Because of this, the quality will necessarily be compromised. At best, the DVD quality is significantly under the quality of an executable show because the resolution must be compromised to fit the "standard" being used.

Best regards,

Lin

[goddi]

"I'm not sure why you are not seeing some difference in the playback when choosing different parameters, you definitely "should" see differences. Codecs (compress/decompress) algorithms resident on your computer account for different choices on the "Create Custom AVI" menu. There are numerous codecs and whenever you install new software you may be adding to the list. You can also download free codec "packs" such as the "ACE Mega Codecs Pack" where you can install as many as you wish. "

When I playback using an AVI that I have made, using Winamps, even though I had set the datarate to, say, 3000, it shows it is playing at around 600. I already had the ACE Mega Codecs Pack installed. And as I said in my other post, the upside/down problems seemed to happen after I installed ACE. Then a re-install of the free DivX codec corrected the problem. However, when I re-ran ACE, it wants to uninstall my DivX version, indicating it is version 6.25--perhaps an older version. Not sure what to do here. The DivX I installed said it was 6.3. As you can tell, I am a real novice when it comes to using Codecs. There seems to be so many variables.

Thanks for your help. Gary