batch to encode final output <64MB

[marcorocchini]

Hi
and however Im' a cat
however.


If possibile I would like to do a batch that encode my .mxf source into 1 final MP4 for whatsapp of 64MB
whatever the resolution and duration of the source, eventually scaling from HD to SD in case of length of the original video over 3 minutes.

But the audio part of the final output mp4 file, presumably has to be built and calculated first, so that all the video part corresponds to a precise remaining size/bitrate. For example, if the audio part weighs 3MB, of the 64, it means that the video part can be a maximum of 60-61 MB. However the final file cannot be generated larger than 64MB. Is it possible to do all this in command line and with ffmpeg? thanks

[jagabo]

The definition of bitrate is:

stream size / running time = bitrate

So get the running time of the video and encode at the required bitrate for your desired stream size.

[marcorocchini]

oh wow


[Attachment 68998 - Click to enlarge]

absolutly helpful

[jagabo]

You already know how to do each of the required steps. Just put them together.

[marcorocchini]

but I'm a ***, for kindness be patient: my limited brain however

.

If we consider a source like this:

https://www.swisstransfer.com/d/5ed752dd-32de-46e9-af42-9ac2425127ed

is a video MXF file, 566 MB, 1 min 18sec, HD with audio. How to tell to ffmpeg to generate a .MP4 x264 (also without audio) of exactly and not over 60 MB using double pass?

[jagabo]

60000000 bytes * 8 bits per byte / 78 seconds = 6153846 bits per second

[marcorocchini]

wonderful ***

but :

for kindness : maybe I need to do some little operations, if possible.

Supposing a source (not too big files) like this:

https://www.swisstransfer.com/d/83b7611e-94e2-4ee2-a358-7cfae3ad0cba

a Source.mkv video file 1920x1080 50i, 1 minutes and 29 second. Audio on 2 track, track 2 don't consider. Track 1 have a L + R channels and is the only to be encode

my target should be encode the source.mkv in a MP4 file for whatsapp of exactly 63 MB. And where the audio part is something like a 128 kbs VBR stream

So the commandline for ffmpeg how it should be done?