x264: 480x192, what kbps?

[joshbm]

Hey all,

I am brand new to H.264 and especially the mp4 wrapper world (although not too new to the MPEG-4 world). I was wondering what would be a good kbps for a 480x192? I am going to put this on a mini-CD and show off some of my work, so it needs to be small and excellent quality.

Thanks!
- joshbm

[chongy5]

How long does the video last for, what is the size of the mini CD etc etc - there's a million things we need to know before we can find a suitable bitrate.

[nm]

Try 200-300 kbps, or maybe a bit more if you have a very noisy source.

[foxyshadis]

Mini-CDs are 210mb. Just use a bitrate calculator to fill it up. If it's a really short video, like 5-15 minutes, use crf 16 or 18 to get the best quality, since there's no way you could use the whole cd. Using crf quality values usually makes more sense when you don't have an exact target size.

[Wishbringer]

Good values for XviD were 0.19 bits per pixel,
i've tried 0.17 bits per pixel for AVC and got good results.

But in general it depends like everything on sources.

480(width)*192(height)*29.97(fps)*0.17(bpp)/1024=459kbits/sec

I personally use -crf (18-20) and of course filters like DeGrainMedian, RemoveGrain, FF3Dfilter etc.

[chongy5]

Just a side note, i always thought anything under 0.2 bits per pixel in xvid looked bad. Just my view.

[Sirber]

you can go with smaller bpp with x264, like 0.10

[xyloy]

Just a side note, i always thought anything under 0.2 bits per pixel in xvid looked bad. Just my view.
It's mine too. ;)

[smok3]

Good values for XviD were 0.19 bits per pixel,
i've tried 0.17 bits per pixel for AVC and got good results.

But in general it depends like everything on sources.

480(width)*192(height)*29.97(fps)*0.17(bpp)/1024=459kbits/sec

I personally use -crf (18-20) and of course filters like DeGrainMedian, RemoveGrain, FF3Dfilter etc.

0.17 seems reasonable, but crf 18-20 should get you quite bigger bpp on the end, no?

[joshbm]

Okay sorry guys! My internet was down! Now that I'm online I can give you the full skinny:

Source: DVD MPEG-2 8000 kbps CBR
Destination: 9:55, 480x192 MP4 Container, 23.976 fps, ABR AAC stereo 128 kbps audio

I understand mini-CD's are 210 MB, but the only problem is I have a couple of smaller movies (320x240, MP4 again) to put on as well. This mini-CD is basically my resume/portfolio for what I have done. So it includes images and such (autoruns an html, then they can view videos by clicking on each). So I cannot simply use a bitrate calculator to fill up the CD.

I tried 1000 kbps 3 files (1 is 480x192, 2 are 320x240, actual bitrate 1000kbps-128 kbps audio=872 kbps). I kind of like how that looks, but it pretty much fills the CD up (~179 MB). So I'd like a little more leeway to have room for extra files and documents.

Regards,
joshbm

[Imperial Llama]

No one can possible tell you what bitrate to use as it will depend on the complexity of your source material. Maybe 200kbps will be enough; perhaps you need to use 600kbps.

Instead of trying lots of different bitrates hoping to get an acceptable quality, just set a target quality (--crf 20 is a good starting point imo) and let the encoder choose the bitrate. This way you will ensure that each file has the same quality too.

[leiming2006]

To control the size 2-pass is a easy way even it may takes you much time.

[foxyshadis]

How about this: Fill the cd with everything incidental you think you might need, and give yourself 5-10 mb leeway. Encode all three videos at q2 in xvid (fast), then divide the remain free space on the cd into the three files following the ratios the xvids show.

Hey, if you need perfect precision, there you go. If you don't I'd just encode at crf 18-26 in steps of 2, starting at 22, and see which group "felt" like the right size, small enough but good quality, since it's obviously a personal decision. :p

You might need to include vlc too, of course.