Default vs. software vs. quick sync

billmich

Member
How will VRD know what my target size is? I am assuming that I manually enter it.... my target will always be 25 GB BD-R (I think that equates to about 23.8 GB file size..)

Dan, Why is it that you DON'T use that option? Is the calculator option better?


If the one pass doesn't consistently hit my target, then I could always lower my target slightly to give me more 'wiggle room'
so I still have the option of 1-pass or 2-pass software, or 1-pass QS by doing this?
 
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Danr

Administrator
Staff member
1) You set it in the profile. Copy and edit an existing profile so you won't have to enter each time.

2) I don't worry about fitting things in fixed space, so I don't use that option. I keep all my media on a home server and tend to use a % of the source bit rate. I.e. For MPEG2 > H.264 I use 50%. Personally, I don't recode all that much on a day to day basis. Most of my editing is MPEG2 > MPEG2 intelligent without recoding since the FireTV's will play those files quite nicely using Kodi. When I travel I'll recode to H.264 for the iPad. Sometime I'll do an H.264 recode for Roku since that's the streaming box we have in the bedroom, but that's not too often. I always use QS except when testing a specific codec.

3) Yes, you have 1 & 2 pass software and 1 pass QS.
 

billmich

Member
So I finally got around to playing with some of these settings. I have a 6 hour file of the Super Bowl. Total file size of 35 GB. Recorded in .WTV format from my HDHomeRunPrime

When I save the entire file MPEG2 (WTV actually)--> H.264 the process took 87.7 minutes (I used Quicksync)

Then I went in and adjusted the target file size to 23.5 GB (the max size I can burn onto a BD-R disc) and did a MPEG2(actually WTV)--> MPEG2 save. The process took 83 minutes (Again using Quicksync) - the resultant file, however, was 24.1 GB, which is too big.
So I tried again and set my target to 22.5 GB and the process took 81 minutes and resultant file was 23.1 GB (which works for me) - again I used Quicksync.

Questions:

1) When I used the 'target size' and the software encoder, the time remaining clock indicated that it would take about 3 hours, is Quicksync really that much faster than the software encoder in these types of situations? (it was set for software 1-pass)

2) If there is going to be a re-code anyways, such as these situations, does changing the drop down box of "intelligent re-code " or "forced re-code" do anything? Or is that basically for when you WANT to do a full re-code when it normally would do the fast intelligent re-code?

3) Keeping the original file size constant, will reducing the target size cause the save process to take less time?
In my above example it took about 2 minutes less. I kept track of how long it took by the banner that pops up after the save is completed and divided the number of seconds by 60 to give me how many minutes that save took

Normally I wont be trying to take a 35GB file and try to get it under 23.5 GB, usually it is a case of a 26-28 GB file that needs to be converted. I would assume that having a smaller original file will cause the save time to be less as well, am I correct?

If anyone can answer my question or confirm/add to my findings, it would be most appreciated.

thank you
 
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Dan203

Senior Developer
Staff member
With a force recode you have a bit more control over the bitrates, but otherwise it's essentially the same.

The target file size setting is basically a guess. We use the duration of the output to calculate the average bitrate for both the audio and video. Video birate can vary quite a bit depending on how much motion is in the video, so it's best to shoot a little low for high motion content.

The output estimate is just an estimate. It basically works by looking at how long it took to output the first 10% of the video (when it says calculating) then it just assumes the remaining 90% will take proportionally as long. If there was any sort of initial lag then it can throw that off. It self corrects over time, but the initial value can be way off so I wouldn't put too much stock into it.

The amount of time required for a recode really depends on resolution and bitrate. But other factors like resizing, deinterlacing, etc... can have an effect. The ultimate size of the output file doesn't have a huge effect on the process. Although the lower the bitrate the more work the encoder has to do, so all other things being equal it will take a little longer to produce a smaller file.
 

billmich

Member
I realized there's another option for Q2: On the advanced tab, scroll down to Intelligent Recode Options. Change the Bitrate calulation mode to "Target File Size". This should automatically set the average bit rate and force a transcode if the file is larger than the Target size.

Personally, I don't use that option which is why I forgot about it.

Hope that helps.
going back to old thread—— was this feature of target file size included in version 6?
 
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