x264 and specifying a target filesize creates bad mp4

[sirsad]

Here is a sample video of the "bad" mp4.

I'm using MeGUI and the "x264: HQ-Slowest" profile. The source file is recorded using Blackmagic MJPEG (more info here). The autoencode button gives me the option of specifying a file size. I set Average Bitrate to 5000, which gives a filesize of 14.9 MB. The sample shows what happens to the file. I'm guessing it happens whenever there is a lot of scene movement. If I set it to "no target size", then the file comes out to be 3.3MB and inferior quality, but the pausing issues are not there.

This is the video avs file

LoadPlugin("C:\Program Files\AviSynth 2.5\plugins\TomsMoComp.dll")


clip = DirectShowSource("Zealot Nordenwatch.avi", audio=true)
clip = Trim(clip, 4500, (4500 + (clip.Framecount/30)))
clip = KillAudio(clip)
clip = SwapFields(clip)

#overlayclip = BlankClip(length = clip.Framecount, width = 522, height = 168, pixel_type = "RGB24", fps = clip.Framerate, color = $000000)

#clip = Overlay(clip, overlayclip, x = 87, y = 737, mode = "Blend", opacity = 1.0)

clip = ConvertToYV12(clip)

TomsMoComp(clip,-1,5,1)

This is the audio avs

clip = DirectShowSource("Zealot Nordenwatch.avi", audio=true)
clip.Trim(4500, (4500 + (clip.Framecount/30)))

So does anyone understand the x264 settings enough to explain why a larger file has issues but a smaller file doesn't?

[poisondeathray]

If you dont specify filesize, it defaults to 1000kbps (in the presets settings) which explains the 5x smaller filesize

You can manually adjust the bitrate in the profile, but don't save it - then it just gets "placed" in the scratchpad, and the profile isn't overwritten.

I also recall reading that autoencode is broken in MeGUI, and has been reported in the bug tracker

If you just want a certain level of quality, you can use constant quality mode. If you want a set filesize, use a bitrate calculator (from MeGUI) but manually enter the numbers saving to the scratchpad (pressing apply is non-functional right now for the calculator - also reported in the bug tracker)

Also consider posting specfic questions at Doom9 forums - all the authors of MeGUI and x264 post there

I've heard MJPEG from that card is not fun to work with, and uncompressed is the better way to go if you have several hard drives, or using a cineform intermediate codec - again check the capture section at Doom9

[sirsad]

If you dont specify filesize, it defaults to 1000kbps (in the presets settings) which explains the 5x smaller filesize

You can manually adjust the bitrate in the profile, but don't save it - then it just gets "placed" in the scratchpad, and the profile isn't overwritten.

I also recall reading that autoencode is broken in MeGUI, and has been reported in the bug tracker

If you just want a certain level of quality, you can use constant quality mode. If you want a set filesize, use a bitrate calculator (from MeGUI) but manually enter the numbers saving to the scratchpad (pressing apply is non-functional right now for the calculator - also reported in the bug tracker)

Also consider posting specfic questions at Doom9 forums - all the authors of MeGUI and x264 post there

I've heard MJPEG from that card is not fun to work with, and uncompressed is the better way to go if you have several hard drives, or using a cineform intermediate codec - again check the capture section at Doom9

The hope of what I'm doing is to get good visual quality throughout the video with a reasonable file size but since the amount of action in each scene changes drastically, I was going to let the codec do what it can. Just from my tests, it looked like a bitrate of 5000 produces a good compromise. I don't totally understand the difference between CQ and HQ. Is quality defined in bitrate or how good the video looks?

I would not be surprised if MJPEG was causing this issue but I wanted confirmation before I go buy another 7200.11 TB drive. I'm also not sure if 2x7200.11 seagate drives will be fast enough to record uncompressed. Virtualdub reports a 20MB/s rate with 5.8:1 MJPEG compression. So I would need at least 120MB/s sustained.

I'll post in the doom9 forum to see what they suggest.

[sirsad]

Blah at the 5 day wait before posting on the doom9 forum!

[sirsad]

My previous tries at playing this video was using VLC. I tried MPlayer and it played the video fine! I guess MPlayer is my new video player...

[hello_hello]

Delete the presets you're using. They're no longer installed when installing MeGUI and they're outdated (there's now a warning about using them in the first post of the doom9, MeGUI presets thread. MeGUI has a target device option when setting up the x264 encoder. The idea being you use the target device option if you need to, select an x264 speed preset and save it as your own MeGUI preset (I generally select DXVA which sets the AVC level to 4.1).

The HQ preset you're using is probably similar to using the standard x264 settings and a speed preset of Slower or VerySlow. CQ in this case refers to constant quality (for reasons I don't understand it's called constant quality if you check the x264 advanced settings box, and target quality if you leave it unchecked, but it's the same thing). The encoder still does the same thing distributing the bits as when running 2 pass encoding but instead of setting a file size you're setting the quality. Constant quality encoding is the way to go unless you need to hit a particular file size, and it's much faster as it only requires a single pass. The CRF value is just labelled "quality" in MeGUI. It defaults to a value of 20. Most people probably use values of between 18 and 22. The lower the quality value the higher the quality and the larger the file size. CRF (quality) 20 is probably a good place to start.

[hello_hello]

Blah at the 5 day wait before posting on the doom9 forum!

Yeah it seems fairly silly to me. And then after waiting 5 days, every second new poster finds themselves unnecessarily quizzed regarding the origin of their files if they have the audacity to be inquiring about converting anything other than a disc.

[poisondeathray]

5 days is nothing compared to the 3.5 - 4 years for your reply.... heeelllloooooo

[Atak_Snajpera]

Yeah it seems fairly silly to me. And then after waiting 5 days, every second new poster finds themselves unnecessarily quizzed regarding the origin of their files if they have the audacity to be inquiring about converting anything other than a disc.

This is not silly. Delay period was added to reduce spamer's activity. Besides new users should have read forum's rules.

[hello_hello]

5 days is nothing compared to the 3.5 - 4 years for your reply....

Okay, I'll bite. What are you referring to there?
Edit: Ohhhhhhh.... now I get it. I didn't realize I was posting in a 4 year old thread. How did I manage that? No wonder the OP was using the old MeGUI presets. Okay...... that was silly.

This is not silly. Delay period was added to reduce spamer's activity. Besides new users should have read forum's rules.

Should've, would've, could've....
There's no mention of the delay period in the forum rules. It's mentioned on the initial sign up page, and yes it's silly given pretty much all other forums can make do with email verification and captchas to discourage spammers. Some of the more spammer paranoid forums let you post immediately, but new posts won't appear until they've been approved by a mod (usually happens within 24 hours), which rates far lower on the silly scale and is even more effective at stopping spammers.