Bit Rate

[shapper]

Hello,

I am converting all my DVD movies to DivX. I am looking for good quality rather then extreme size reduction.

I know that I should use half of the Bit Rate of the original movie.

How can I get the bit rate of the original movie?
And I suppose I should use rounded bit rates like 2000, 2200 ... and not 2101, 2312, ...

Could someone advice me on this?

Thanks,
Miguel

[jagabo]

Forget bitrates. Use Divx's constant quality, "1-pass quality based", encoding. Select the quality (quantizer) you want and encode in a single pass. Try a quantizer of 3. 2 if you want even higher quality (some Divx/DVD players may have trouble at this high a quality setting though), 4 or more if lower.

[shapper]

I am using http://www.avs4you.com/AVS-Video-Converter.aspx.
I don't get those options ... I get the Bit Rate.

[guns1inger]

If size really is no object, follow Jagabo's sound advice. If you do need to balance size control, I find that between 10 - 15 MB per 10 minutes of footage does a good job. I encode SD digital TV streams, which are PAL DVD resolution with average bitrates of around 5500 - 6500 kbps. I use 10 MB per 10 minutes of footage and get no macro-blocking, even on shows like Top Gear. I use AutoGK to encode.

[shapper]

When size isn't a problem isn't better to convert all the VOB files into a single MPEG file?

And something I don't understand: How can I add othe language subtitles to my movie?
Are the subtitles inside the Movie file or outside?

Thanks,
Miguel

[guns1inger]

It depends on the software you are using to convert the files. For AutoGK I would just rip the title I wanted into a single VOB (DVD Decrypter can do this) or merge them afterwards with VOBMerge, then convert. I don't do subtitles much, so I'll leave that for someone else to address.

[shapper]

I will rip my DVD using the following definition for a test:

Input

Video:
7500 kbps; 25 frames/sec; 16:9; MPEG 2 Video; 720x576 px
Audio:
384kbps; 6 Channels; 48000Hz; Dolby Digital AC3

Output

Video:
4000 kbps; 25 frames/sec; 720:576; MPEG 4 (DivX/Xvid); 720x576 px
Audio:
224kbps; 2 Channels; 48000Hz; MP3

I am using Single Pass Encoding.

Any suggestion to my first test?

Thanks,
Miguel

[jagabo]

If you are going to keep the same frame size be sure to set the MPEG4 display aspect ratio flag to match your source, 16:9.

4000 kbps CBR (constant bit rate) encoding isn't the best. If you can't use single pass constant quality encoding use 2-pass VBR (variable bit rate) encoding.

Why don't you just keep the AC3 audio?

I just tried out the software you are using. In the Profile Editor click on the Advanced button next to the Video Codec setting. In the MPEG4 Settings dialog click on the Bitrate button to change it to Target Quantizer (constant quality encoding). Set the quantizer to the desired value with the slider below the button. Now you'll always the quality you specify. The bitrate will be whatever it takes to deliver that quality.

[shapper]

Hi,

I found it! Thanks.
I was trying to find a way to keep the AC3 ... It seems not be possible. No idea why.
The same way with 16:9 ... It always place the movie dimension. I will email them.

On the quantizer slide I get only fixed values ... not able for example to set 2.0 ... only 2.5, 1.82, ...

Is this a software problem? Or there is a reason for this?

Do you know if PlayStation 3 reads the movies if setting the value to 2.5?

Thank You,
Miguel

[jagabo]

I was trying to find a way to keep the AC3 ... It seems not be possible. No idea why.
The same way with 16:9 ... It always place the movie dimension. I will email them.

That is the problem with all-in-one software that does everything for you. You don't always have the level of control needed to do what you want. And if anything goes wrong there's nothing you can do to fix it.

On the quantizer slide I get only fixed values ... not able for example to set 2.0 ... only 2.5, 1.82, ...

Is this a software problem? Or there is a reason for this?

It's simply poor programming. In addition to the slider they should have let you type a number into the box. You don't need to get an exact value. Internally the codec uses only integers. If you specify a non integer value the program will alternate between the value above and below it to give the correct overall average. So if you select 2.5 the codec will alternate between 2 and 3 so that half the frames get a 2 and half get a 3. If you enter 2.333 it will use a sequence line 2 2 3 2 2 3 2 2 3...

Do you know if PlayStation 3 reads the movies if setting the value to 2.5?

I don't know what the PS3's limitations are. It will probably work.

[shapper]

Hi,

I will follow your suggestions and use AutoGK.

I am looking at it and I already have a few questions but I will post a new thread since this is a new subject.

Thank you,
Miguel