Avidemux issue...

[Sedoc94]

Hey,

When I'm encoding my video (x264) it goes through Phase 1... and then Phase 2 and then sometimes it crashes..

I'm wondering why it's going through two phases?

I mean.. I though when Phase 1 is done, that it's done with encoding..
But no it goes again through phase 2... so totally it takes 2 hours to encode from mkv to mp4.

Is this common?

Or is there a way to make it finish quicker?


Thanks,
Sedoc94

[CSULB71]

You must have "Two Pass" encoding selected. First pass checks the video for bitrate allocation, second pass does the actual encoding.
2 hours to encode normal? Depends on the length of your video, encoding bitrate selected, filters used, etc.

[Sedoc94]

Well... an MKV file of 145mb, subtitle filter (.ass), length: 23min. Encoded with x264 into .mp4..
1 hour to do Phase 1 and 1 hour to do phase 2...

And I don't notice any speed ups when I set the Priority from below normal to Above Normal or High...

WinMenc does this process within 1 hour.. but since it doesnt support the effects of .ASS my only way is Avidemux.. ^^

[CSULB71]

You can probably get acceptable quality results with one-pass encoding using an appropriate quantizer setting -- that should cut the encoding time in half (one hour vs. two).

"And I don't notice any speed ups when I set the Priority from below normal to Above Normal or High..." -- no, that setting doesn't affect encoding speed, as far as I know.

When you use WinMenc, are you using a one-pass process? That would explain the quicker time.

[Sedoc94]

And how would I do that?

Sorry I don't know much about this.. ^^

[CSULB71]

I'm familiar with XviD and DivX codec settings -- they give you codec "configuration" settings where you can select one-pass or two-pass, quantizer (quality ) or specific bitrate, motion, etc., so I assumed the x264/mp4 codec you are using would have something similar.

[jagabo]

And I don't notice any speed ups when I set the Priority from below normal to Above Normal or High...

Changing the scheduling priority would only make it faster if you were running some other CPU hungry application at the same time. When multiple programs are asking for CPU time Windows will give the one with the highest priority more CPU time than those with lower priority. If you are only running one CPU hungry application it gets all CPU time regardless of its priority.

I usually encode at idle priority (note that AviDemux only goes down to low). Then if I want to use the computer for anything else the encoding has almost no impact on system performance.

Regarding single pass quality mode in Avidemux/x264: set the Encoding Mode to Constant Rate Factor (Single Pass). Set the Quality to somewhere between ~18 (very high quality) and ~26 (medium quality).

[poisondeathray]

you're probably using different encoding settings, quality settings, rate control modes between the 2 applications.

another option for hardsubbing .ssa is textsub() in avisynth

[Sedoc94]

Now I have another issue... and that is that the Video is out of sync with the audio&subs...

Thats weird because in the source file everything is synced...

[CSULB71]

Quote: "Now I have another issue..."

Is the audio being out of sinc a new issue, after trying jagabo's suggested codec settings, or did you just now discover it and you had it all along from your earlier encodings?

[jagabo]

If the audio is off by the same amount over the entire video you can use the audio shift feature in AviSynth to adjust it.

[Sedoc94]

Well the thing is that in the beginning the audio is in sync, but at the end it's out of sync.

Is there maybe any other program that can encode mkv to h264 mp4 with .ass subtitle?

[poisondeathray]

you can do it through avisynth + any program that accepts avs scripts (i.e. almost all of them)

e.g.
FFMpegSource2("video.mkv",atrack=-1)
TextSub("video.ass")