anyone here experienced with ffmpeg?

[Panupat Chongstitwattana]

Using Zeranoe ffmpeg build for windows.

I'm sending playblast video (YUV compression) to ffmpeg for h.264 compression outputting to Quicktime mov. But I'm having problem that sometimes the output video has messy green screen added to the end. (for example, 90 frame avi, got 50 frames of messy green added to the end)

The problem doesn't seem persistant, if I restart windows, the first few playblasts wouldn't have this problem. After a while tho it'd start doing it randomly. Tried it on multiple machines and got the same result.

Is it because h.264 doesn't like my resolution? When I playblast at 1920x1080 it seems to always work.

[deanareeno]

Are you using Quicktime Player to play the .mov file on Windows? In the past that's the only time I've experienced 'messy green' when viewing back playblasts. Solved by doing the following in Quicktime Player:

Edit > Preferences > Quicktime Preferences > Advanced > Video > click 'Safe Mode (GDI only)'

Try that, or try another player (like RV, or VLC, etc.)

If that doesn't work the it's back to the drawing board.

Cheers,

-DW

[Emre Yilmaz]

One thing the OP said that jumped out for me-- "Is it because h.264 doesn't like my resolution? When I playblast at 1920x1080 it seems to always work."

How much choice do the users of your tool have over image size?

While I'm not familiar with ffmpeg on windows, I have a memory that h.264, MPEG-4 and similar encoders can be a little finicky about image sizes and dimensions.  My memory is that it isn't so much the overall size, but that the dimensions need to be a multiple of some underlying block size, like 4x4 or 16x16, though I don't recall specifics.  Anyhow, if the pattern you're seeing is "certain dimensions work and others don't"-- for instance let's say supplying dimensions 1920x1080 always worked, but supplying dimensions 1921x1081 often didn't-- this may be an underlying issue you may want to look into.

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[Mark Jackson]

http://markj3d.blogspot.co.uk/search/label/Playblast

not sure if any of that helps, but we've been through a lot of pain in the past with Codecs!

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Mark Jackson
Technical Animation Director
http://markj3d.blogspot.com/

[Panupat Chongstitwattana]

Hi all.

@ deanareeno. Yes I was using quicktime player! But the output also shows up weird on VLC and WMC too. I'm guessing I'm not using the codec right :(

After a lot of experimenting, the problem seems really random. Usually the first few times after restarting, the conversion seems to be fine. After that it's almost always screwed up. I tried lots of standard resolution 720p, 800x600, 320x160, the problem seems to show up on all of them. Except 1920x1080... really weird.

But I had an idea on my way home that maybe Maya's compression isn't playing nice with ffmpeg. I'll try playblast to image sequence tomorrow and see what happens.

[Panupat Chongstitwattana]

Hi everyone.

After experimenting more I think I'm getting more predicable result now. A couple things I had done at home.

- playblast out as PNG sequence. FFmpeg reads jpg sequence much faster with less CPU, but for some reason it always get the aspect ratio of jpg wrong.
- force resolution to be divisible by 16.

Will have to test it at studio. A couple notes about codecs

MJPEG - very fast to scrub through in quicktime even at full HD. Although it's quite larger than h.264. -q:v is the compression. 0 = no compression, 25 max.

working command = ffmpeg -y -i d:\temp\test.%4d.png -r 30 -vcodec mjpeg -pix_fmt yuv420p -q:v 10 -f mov -an mjpegQV10.mov

H 264 - A little slower to scrub timeline but file size is much smaller. Needs to keep bframe low to help with timeline scrubbing. Eventually I just disabled it (-bf 0). crf seems to be the quality, if set higher than 25 the result gets splotchy.

working command = ffmpeg -y -i d:\temp\test.%4d.png -r 30 -vcodec libx264 -vprofile baseline -crf 22 -pix_fmt yuv420p -bf 0 fromPng.mov

best regard,
P Chong.