[FFmpeg-user] 4K Way to large to stream

Carl Zwanzig cpz at tuunq.com
Tue Jun 29 19:30:34 EEST 2021

On 6/29/2021 5:57 AM, rbarnes at njdevils.net wrote:
> The ' -s ' switch was not very informative from what I could discern in the
> document.  I was unable to locate a parameter list for that switch. 

'-s' and '-r' are under 5.5 Video options 

-s[:stream_specifier] size (input/output,per-stream)
     Set frame size.

-r[:stream_specifier] fps (input/output,per-stream)
     Set frame rate (Hz value, fraction or abbreviation).

(I will note that with the optional stream specifier directly after the 
switch (i.e. "-r[") they're much harder to search on; that's a different issue.)

>  When I replied back, I made the
> assumption that you were trying to assist in preserving the 4K stream and I
> was reading the switch documentation incorrectly and asked for
> clarification.

Like the "Good/Fast/Cheap - Pick two" metaphor, you have hit the 
quality/file-size/bandwidth trade-off. To keep the resolution at 4k and at 
good-to-excellent quality, perforce the files and bit-rate will be large- if 
you want the file to be smaller, even with very fancy encoding something 
must be discarded, could be resolution, could be frame rate, could be "quality".

There's also the point that in many cases, super high quality is effectively 
wasted, for instance, 4k is only effective if the viewer has a 4k display; 
5.1 sound is only effective if the listener has 5.1 playback equipment -and- 
the sound was mixed for that. etc.

It's also been said “Never underestimate the bandwidth of a station wagon 
full of tapes hurtling down the highway.” (Andrew S. Tannenbaum); you may be 
better served by copying the file to a flash drive and mailing that. If 
everyone pushes "start" at the same time, you can still watch it together.



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