Bitrate vs quality vs file size - PS3 Mp4 specific

[NoOne2]

I've been using PS3Video 9 to convert VOB's into MP4's for my PS3.

I recently upgraded to a OC'd Q6600 and found that application was not running all 4 cores at full speed.

In another thread I asked for some suggestions on apps that would use all 4 cores and was given some great suggetions. In my testing of different file bitrates and compression methods over the past few days I'm trying to get a handle of what is the best setting for playback.

I never did 2 pass on Ps3video 9 because it didn't work for me. Single pass conversions off of good original content gave me good results at 3072br and a 480p resolution. This gave me an average file size of 3.2gb for just under 2 hours of video or an original MPEG2 file size of 6.1gb.

Quality was decent but there was a sheering effect that I've even seen in MPEG4 broadcasts over Dish network in HD.

Lower quality content gave me pretty poor results.

I tried RipBot and found at the CQ24 setting(beats me what that is) I got a file that was 1.6gb at 480p, had minimal to no sheering but was just a little on the soft side.

With a 2 pass 2048bit setup I ended up with a file at 2.12gb and slightly better quality than the CQ24 file but maybe not worth the extra 45 minute encoding time.

So what I'm looking for is the sweet spot between file size, bitrrate, and time to compress.

I was really suprised how much better both files from RipBot turned out compared to PS3Video9 considering they were half the size.

Anyone found a good setup for the PS3 and MP4?

[ilovejedd]

The CQ24 is for constant quality/quantization. It's single pass so it's faster than doing encoding using 2-pass average bitrate. To increase quality with 0 to minimal increase in encoding time, change CQ to something lower, I guess. Maybe 23 or 22 instead of 24?

[NoOne2]

So lower is better?

I just took a section off of a Superbit DVD and am encoding it at various rates to see what the final product will look like. I never realized that lower is better for CQ. I'll add another run at the lower rate.

Maybe thats why the CQ encode took longer than the 2 pass when I first tested it.

[ilovejedd]

I never realized that lower is better for CQ. I'll add another run at the lower rate.

Maybe thats why the CQ encode took longer than the 2 pass when I first tested it.

CQ should not be slower than total time for a 2-pass encode assuming all things are equal. Also, keep in mind that since CQ is based on quality, file size is largely dependent on complexity of a source. If you have a highly complex source, then you're looking at larger files. 2-pass encoding is ideal if you need to keep files under a certain size/bitrate. You could always leave your PC batch encoding overnight.

By the way, have there been any tests on using a PS3 for video encoding? Looking at the folding@home stats, the cell processor seems to be pretty powerful and might be suitable for video encoding.

[Dark Shikari]

x264 shouldn't be used with CQ mode; it should always be used with CRF mode when doing a single-pass quality-based encode. CRF always outperforms CQ.

[NoOne2]

I took a VOB file from a Superbit DVD with complex action and good detail.

Original bitrate is 8mbps MPEG2 18 minutes in length.

My encoding times and these are rough numbers were:

2 pass 2048mbps 12:25
2 pass 3072mbps 14:00

CQ24 6:52
CQ22 9:00

These are rough numbers, I was doing somethings in the background at the same time but my file sizes were:


Original 1,048,574kb
2pass2048 287,850kb
2pass3072 423,020kb
cq22 269,196kb
cq24 201,641kb

Quality wise the original was obviously best then the 3072 then VERY VERY closely by the CQ22. CQ24 and the 2048 showed a lot of interlacing lines.

I'd pick CQ22 as the winner based on mid range size and extremely close quality to the 3072br file.

These were viewed on a 47" 1080p LCD setting the PS3 to full size. The biggest problem with the image was interlacing during certain motion scenes. Complex scenes seemed OK it was scenes were almost everything was static except for a few moving parts, even 4-5 frames they would get this interlaced look to them, then go back to normal.

I can post up screen caps if that is allowed with all the legal stuff.

When you say CRF mode which application supports it?

Once I get down to a set of 2-3 different formats I'll try something with lower quality like the original Blade Runner which has to be one of the worse DVD conversions I've seen and something in the mid range also to see how they fair.

Is there any specific to get rid of the interlacing effect or just a higher bitrate?

[ilovejedd]

The biggest problem with the image was interlacing during certain motion scenes. Complex scenes seemed OK it was scenes were almost everything was static except for a few moving parts, even 4-5 frames they would get this interlaced look to them, then go back to normal.

I can post up screen caps if that is allowed with all the legal stuff.

When you say CRF mode which application supports it?

Once I get down to a set of 2-3 different formats I'll try something with lower quality like the original Blade Runner which has to be one of the worse DVD conversions I've seen and something in the mid range also to see how they fair.

Is there any specific to get rid of the interlacing effect or just a higher bitrate?

Yeah, screen caps are fine. That should fall under fair use. Just post to an image sharing site (imageshack?) instead of adding an attachment. Attachments need to be approved, iirc, so there's a bit of waiting period.

x264, mencoder, etc all have the crf option. RipBot is probably a front-end for either or both but I haven't used it so I wouldn't know where to change the setting. I've also never used crf as I encode in 2-pass average bitrate.

I don't think x264 can encode interlaced video like Xvid. You might have to deinterlace/ivtc the video via Avisynth prior to encoding. Hmm, can't help you much there, though. I'm lazy and my scripts (for PSP) are usually a simple:

loadplugin("dgdecode.dll")
loadplugin("decomb.dll")
loadplugin("nicaudio.dll")
video = mpeg2source("video.d2v").fielddeinterlace().bilinearresize(320,240)
audio = nicac3source("audio.ac3").amplify(3)
audiodub(video,audio)

Somewhat primitive and definitely not the highest quality possible but it has worked for all my DVDs, so far.

[Dark Shikari]

I don't think x264 can encode interlaced video like Xvid. Yes it can, with --interlaced mode.

[deets]

ripbot uses CRF when you select CQ mode, then CRF is available in the drop down menu.

maybe thats why it varies so much from regular CQ mode.