Can I keep bitrate and quality converting from DivX to MPEG2?

[aguinsburg]

Hi,

Having for example a DivX compressed video with a bitrate of 1500 Kbps and if I want to convert to MPEG2, then using same bitrate make same quality video? In other words, if I preserve the original bitrate, I preserve quality?

Thanks

[redwudz]

No, you would need a higher bitrate for MPEG-2 compared to Divx. I do simple Xvid to DVD conversions with ConvertXToDVD. A 700MB video will make about a 1.5GB DVD file with that program.

You can use a bitrate calculator from 'Tools' to the left and it will tell you the bitrate needed to fill a DVD. https://www.videohelp.com/tools?s=1#1 Bitrate is based on the run time of the video, it has little or no relation to what the original bitrate was before encoding.

But you do have to watch not to get it too high. When you have a MPEG-2 bitrate over about 8500, some players may not be able to handle it. That high of bitrate wouldn't improve the quality much anyway. It depends on your source quality. If it's a typical Divx movie conversion, it's not that great of quality in the fist place.

But as far as quality when encoding Divx to MPEG-2, yes, you should easily be able to get the same quality.

If your final destination is a DVD, you might look to the upper left for 'What is' DVD, and you will see the DVD specifications, including bitrates.

[guns1inger]

depending on the headroom in the original encoding, the conversion rate is usually around 4:1 to maintain the quaility of the original. That is, mpeg 2 requires around 4 times the bitrate of mpeg4. ConvertXtoDVD comes closest at lower bitrates, but it is still usually around 2.5 to 3 times the original bitrate, although the current version maintains a realistic bitrate better than the freeware version, DivxtoDVD.

However bitrate is only part of the story. Most Xvid/Divx encoded files also have a reduced resolution in order to maintain quality at lower bitrates. When converting to DVD, you have to resize these to DVD compliant resolutions. Depending on how you resize, you may find you have to filter the output to maintain the sharpness of the original. Tools like ConvertXtoDVD won't do this for you, which is why the best quality can really only be achieved through doing this by hand using avisynth or virtualdub and a good encoder.