AVI to MPEG smallest bitrate?

[michcio]

hi there !
I have used HCEnc for a long time now while converting AVI to MPEG (.m2v) but I do always set avarage bitrate to 1900 kb/s to get as small file as possible...but is really 1900 the smallest one I can use and still have quite good quality on my .m2v files?

thankfull for any help!

michcio

[Baldrick]

what resolution/video frame size are you using? 720x576?

[guns1inger]

1900 is low for half-d1, but should be fine (or even more than necessary) for VCD resolution.

As Baldrick has indicated though, you need to provide a lot more information in order to get a useful answer.

[jagabo]

If you want a specific quality rather than a specific file size use Constant Quantization (constant quality) encoding in HcEnc. It will give you the smallest file it can for the requested quality.

[michcio]

thank you very much for all your answers guys!

what resolution/video frame size are you using? 720x576?

here is some info about my .avi file

Codec: XVID
Name: XviD Dev ver. 11-Jun-03
Audio Codec: 0x0055 MPEG-1 Layer 3
Info: 48000Hz  115 kb/s tot , Joint Stereo
Pics/s = 23.976
Frame/s = 23.976
pic ( w x ): 624 x 464

and from this I want to make a .m2v in 720x480 (I'm doing a NTSC DVD)

1900 is low for half-d1, but should be fine (or even more than necessary) for VCD resolution.

As Baldrick has indicated though, you need to provide a lot more information in order to get a useful answer.

as said I am not making a VCD but a DVD 704. Is 1900 also to low for DVD 740 as for half-d1? I have always used DVD 740 and 1900 and it has worked just fine...

If you want a specific quality rather than a specific file size use Constant Quantization (constant quality) encoding in HcEnc. It will give you the smallest file it can for the requested quality.

nice function didn't know that that was able in HCEnc though I don't want to have the badest quality...my .avi file got a nice quality and then when I make a .m2v file from this .avi (using 1900) I got nice result though I have heard some people NEVER go belo that kb/s...but when encoding this kind of .m2v I got a file twice so big then my .avi...now wouldn't it be able to after converting from .avi to .m2v still have the same filesize AND quality?!

thankfull for answers as usual

michcio

[michcio]

..

[jagabo]

The bitrate required by every video is different. An hour long still frame may require only 1 kbps to have an output file that has minimal macroblocking and detail loss. An hour of between channel static might take over 50,000 kbps (this would not be compatible with the DVD spec, of course). Most video will fall somewhere between those two extremes. But there is no absolute rule that states "no matter what your source you must use at least X kbps bitrate to maintain quality."

If you need to put a 2+ hour movie on a single layer DVD your best bet is usually to use 2 (or more) pass VBR and to fill the DVD. If you want a particular quality level use constant quantizer encoding then put as much as will fit on each DVD. The latter works especially well with 22.5 minute TV episodes or other short videos where you can just put however many episodes fit on each DVD.

[michcio]

The bitrate required by every video is different. An hour long still frame may require only 1 kbps to have an output file that has minimal macroblocking and detail loss. An hour of between channel static might take over 50,000 kbps (this would not be compatible with the DVD spec, of course). Most video will fall somewhere between those two extremes. But there is no absolute rule that states "no matter what your source you must use at least X kbps bitrate to maintain quality."

If you need to put a 2+ hour movie on a single layer DVD your best bet is usually to use 2 (or more) pass VBR and to fill the DVD. If you want a particular quality level use constant quantizer encoding then put as much as will fit on each DVD. The latter works especially well with 22.5 minute TV episodes or other short videos where you can just put however many episodes fit on each DVD.

ah ok thanks for your response jagabo! ...I want to put TV episodes on a DVD and as many as I can but each of my episodes are about 45 min and not 22,5 shall I still try using the constant quantizer?!

michcio

[jagabo]

ah ok thanks for your response jagabo! :D...I want to put TV episodes on a DVD and as many as I can but each of my episodes are about 45 min and not 22,5 shall I still try using the constant quantizer?!

First, I would encode a short representative samples with different quantizers so that you know what quality to expect from them. Pick a quantizer you're happy with then encode a few full episodes and see how big they come out. If all your episodes came from the same source the MPEG2 file sizes will usually turn out in the same ballpark. If it turns out that you can only fit one or two on a DVD you might decide to use multipass VBR instead. It comes down to whether or not you want to invest the time in multipass VBR (which typically takes twice as long as single pass target quantizer) and whether you're willing to waste a little disc space here and there.

[freebird73717]

and from this I want to make a .m2v in 720x480 (I'm doing a NTSC DVD)

1900 is low for half-d1, but should be fine (or even more than necessary) for VCD resolution.

As Baldrick has indicated though, you need to provide a lot more information in order to get a useful answer.

as said I am not making a VCD but a DVD 704. Is 1900 also to low for DVD 740 as for half-d1? I have always used DVD 740 and 1900 and it has worked just fine...

VCD resolution 352x240
1/2 DVD 352x480
Full D1 720x480

All are perfectly compliant for DVD video. The lower the bitrate you use then the lower resolution you should use as well.

[michcio]

and from this I want to make a .m2v in 720x480 (I'm doing a NTSC DVD)

1900 is low for half-d1, but should be fine (or even more than necessary) for VCD resolution.

As Baldrick has indicated though, you need to provide a lot more information in order to get a useful answer.

as said I am not making a VCD but a DVD 704. Is 1900 also to low for DVD 740 as for half-d1? I have always used DVD 740 and 1900 and it has worked just fine...

VCD resolution 352x240
1/2 DVD 352x480
Full D1 720x480

All are perfectly compliant for DVD video. The lower the bitrate you use then the lower resolution you should use as well.

but where do I place my DVD 720 ? which size? I have now tested to encode with 1900 kb/s and I have also selected the constant quantizer in the settings and now I got a file of a size 498 MB instead of 623 MB (the .avi is 350MB) what does constant quantizer do? Does it change me framrate at all?!

thankfull for help

michcio

--------------------

ah while using constant quantizer there is no minimum bitrate nice...the quality after using this function is quite good so I think I will use it

thanks

michcio

[jagabo]

I have now tested to encode with 1900 kb/s and I have also selected the constant quantizer in the settings and now I got a file of a size 498 MB instead of 623 MB (the .avi is 350MB) what does constant quantizer do?

Constant quantizer mode encodes each frame with the same quality (as determined by the quantizer value). If you choose a low quantizer (high quality) you will get a large file. If you choose a high quantizer (low quality) you will get a small file. This is in contrast to bitrate mode where you choose the file size (via the bitrate) and the encoder gives you whatever quality it can for that size.

Does it change me framrate at all?!

No.