Less encoding errors with CQ or 2pass?

[delanejenkins]

Hey guys, just wondering if 2pass encoding can prevent some encoding errors compared to constant quality. I was using constant quality because I'm not concerned about filesize but some of my encodes end up with small errors ("blocks"). Would 2pass be less likely to have these errors?

[unskinnyboy]

If a CQ encode is giving you "blockiness", lower the quantizer (file size will correspondingly increase) and try again. There is no saying whether the "blockiness" will happen in a 2-pass encode or not, because it all depends on what the target bitrate of that 2-pass encode is.

[Sharktooth]

... and obviously, dont disable the inloop deblocking filter ... and use the default inloop deblocking settings ...

[delanejenkins]

I am using a quantizer of 18 with the unrestricted 1 pass high quality preset which has deblocking set at -1,-1. My encoded videos look great 99% of the video but will have Lil glitches sometimes which look like a string or blob of blocks that appears for just a second and then is gone. I'm not sure how better to describe it. If I could stop these sporatic errors my encodes would look fantastic from start to finish. Am I just setting too high of a standard and all x264 encodes will have an error or two?

[Dark Shikari]

I am using a quantizer of 18 with the unrestricted 1 pass high quality preset which has deblocking set at -1,-1. My encoded videos look great 99% of the video but will have Lil glitches sometimes which look like a string or blob of blocks that appears for just a second and then is gone. I'm not sure how better to describe it. If I could stop these sporatic errors my encodes would look fantastic from start to finish. Am I just setting too high of a standard and all x264 encodes will have an error or two?Quantizer 18 is basically visually lossless. Can you post a screenshot of the problem and a sample?

[delanejenkins]

Here you can see a good example of what happens. My video will go from looking incredible to something like this

http://i34.photobucket.com/albums/d135/delanejenkins/example1.jpg

[delanejenkins]

Here is another example. It will do stuff like this then go back to a perfect picture

http://i34.photobucket.com/albums/d135/delanejenkins/example2.jpg

[poisondeathray]

Are you sure it's not a decoder/playback issue? What are you using

Try different player eg.. kmplayer or mpchc. Try different decoder eg. libavcodec, divx h.264, coreavc

Is it a container issue? Try swapping containers. e.g. try .m2ts instead of mkv, or try .mp4 - I've seen this happen

Check your memory integrity e.g. memtest - I've seen this as a cause of something similar

Is it a reproducible issue? i.e. does it occur always at that point, or upon seeking etc..

Rule these things out before uploading a stream

[Dark Shikari]

That's bitstream corruption; the only reason it even looks like anything is because of the decoder attempting (rather in vain) to conceal the errors.

This is usually caused by a broken decoder, disk corruption, or similar, but can also be caused by incorrect bitstream-writing code in an encoder.

[delanejenkins]

I first saw the errors on my hdx 1000 (networked media tank) so I played it on my pc with media player. I then decided to remux it into a "ts" file and low and behold it plays back perfectly. So what gives? I thought mkv was "the container" for x264. Should I try to remux the file again into mkv and see if it was just a botched mux the first time or is this a normal occurence with mkv? I would like to have chapters which
ts/m2ts doesn't support. I guess m4v could also be an option?

And just for reference, I do not have any codecs installed other than ffdshow. I also have been using the mkv muxer in megui to mux my files.