[FFmpeg-user] fMP4 generation speed

Ronak ronak2121 at yahoo.com
Wed Jun 27 07:20:02 EEST 2018



> On Jun 25, 2018, at 6:03 PM, Carl Zwanzig <cpz at tuunq.com> wrote:
> 
> On 6/25/2018 2:41 PM, Carl Eugen Hoyos wrote:
>> 2018-06-25 15:02 GMT+02:00, Ronak<ronak2121-at-yahoo.com at ffmpeg.org>:
>>> 1. Apple does not create temp files
>> Isn't that generally a disadvantage?
> 
> Why would it be (not creating temp files)? Seems sensible from here.
> 
> A better question is why, it appears, is ffmpeg making temp files and where does it put them? If the files are created in the CWD and that's on a spinning drive, it's going to be slow; OTOH if they're created in /tmp and that's in a memory-resident file system it won't be much slower than just keeping large buffers.
> 
> Anyway, different drives for source and output files is usually a very good idea, as is a memory-resident /tmp file system (assuming you have the memory to hold it). Another option is turn off atime on those file systems; updating that can take up a lot of time and usually isn't useful.
> 
> Phil- I'm not sure I agree with you about temp files (in general), a lot depends on the what/where/how-many files are being used.
> 

The temp files are made in the CWD. And they are constantly created and destroyed for every single fragment it seems. I looked into the ffmpeg code and it looks like every single method in hlsenc and dashenc opens and closes these file handles.
I would like to make modifications to the code to fix it, but it's hard to follow exactly which methods to modify.

Just to clarify, I'm making a single fMP4 file here; not multiple.

Does anyone have any pointers? 

> Later,
> 
> z!
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