Mp4 Conversion Settings

Coscast · 2010-12-23 19:05:17

About Bitrate Method:

When i set it to AUTO do i HAVE TO set the 2PASS Encoding ? Or can it be AUTO and 1PASS ?

I know this setting works, but it the 2PASS better with AUTO ?

BTW: CRF+1PASS makes the files nearly 1/3 of the Size as with AUTO+1PASS.

AUTO+1PASS: 29MB
CRF+1PASS: 8MB

for example.

symtab · 2010-12-23 20:03:38

Basically here's how it works.
1. CRF (this means ffmpeg choses the bitrate for you, the filesize and bitrate cannot be estimated, however this produces very good results at small filesizes). I recommend this option.
2. Auto + 1pass (this calculates the bitrate based on the video dimensions (resizing) compared to the standard of 1280x720 (720p)).
2. Auto + 2pass (this calculates the bitrate based on the video dimenstions (resizing) compared to the standard of 1280x720 (720p)). This would get you better video and audio quality (it also depends on the video dimensions). The conversion takes a long time and will use more server resources (CPU).

I tested all these options and i think its better to use CRF (all uploaded good quality videos will have good quality after conversion, filesize is good and the conversion time is smaller than 2 pass/1 pass auto).

To answer your question, you can have auto + 1pass (however i think ffmpeg knows better when calculating the bitrate with CRF).

My conversion method is based on http://rob.opendot.cl/index.php/useful- … ing-guide/ and discussion with a ffmpeg/h264 developer which recommends this. I will do some more debugging once christmas/new year is over and see why the filesize is 3*CRF with auto 1pass (i think it also depends on the uploaded video, for example for the vidz videos, the videos have a small size because the width and height (and bitrate is like 300kb/s) are low and also the audio samplerate is 22050 and audio bitrate is 38kb/s).

Coscast · 2010-12-23 21:20:48

Thank you very much for your explanation.

I'll stay with CRF 1Pass

symtab · 2010-12-23 22:41:53

Is CRF prodoucing good results in terms of quality for you? if not you can increase/decrease (must be integer/float) the value of -crf (you will need to edit libraries/framework/video.php for this).

Coscast · 2010-12-23 23:33:25

Quality is good enough, no need to adjust the settings

Adult Script Pro Community Forums

#1 2010-12-23 19:05:17

Mp4 Conversion Settings

#2 2010-12-23 20:03:38

Re: Mp4 Conversion Settings

#3 2010-12-23 21:20:48

Re: Mp4 Conversion Settings

#4 2010-12-23 22:41:53

Re: Mp4 Conversion Settings

#5 2010-12-23 23:33:25

Re: Mp4 Conversion Settings

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