Producing minimal, Youtube compatible, file sizes

OK I have a ~90 Meg MP3, and a 22kb PNG file. The audio plays for 8 hours 30 mins.

OK to me, 90 Meg plus almost nothing = 90 + a little more.

But I understand this is reconfigured from a single image into 3 nearly 3 hour images (I worked this out) and into jullions of frames per second etc…

When I export it as a standard definition NTSC file, which seems to play on everything and every website will play it…but the file is around 900 Meg.

This is just too huge.

Even the old lost file I extracted the audio from wasn’t that big.

I am new to this software, and I would like a little help.

The main issue is retaining the audio quality and keeping the writing in the ONE *.png legible.

Can someone tell me the settings / configuration, to make VERY SMALL file sizes, that up load to Youtube and almost anywhere, without having to worry about conversion issues from obscure file types and compression methods.

Image quality is at 240P is just fine, and so is a smallish image.

Is there any way to get VERY low frame rates - Like I am no expert at this, but 1 frame per second or minute or hour suits me, but the software does not support it.

I just want to make speaker recordings, with the information about the speaker and subject, in the PNG and the audio to go along with it, so people can listen to them.

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A produce videos of myself speaking, some up to 20 or 30 minutes. My exported file sizes can approach 3GB, unless I use YouTube’s ridiculous codec recommendations, in which case file sizes approach 6 GB.

So my first thought was “For that many hours? 900 MB? That’s tiny!”

That being said, this gave me an opportunity to run some tests I had been meaning to run. I set up a project very similar to yours; an audio file of me speaking, and a PNG I intend to use as a YouTube thumbnail for the real video of that.

Here is the initial setup:


Then I switched over to an all-cpu codec, which is more tolerant of extreme settings.


My procedure then was to change each parameter one at a time, restoring it to original before changing the next parameter.

  • Frame rate
  • Bframes
  • GOP size
  • Quality
    Then a final test with all of these set to the same size-reducing values as the above tests.

Here is the configuration of the codec for that “ALL” test.



Now the results.
First the run times:

Then the file sizes:

As you can see, changing the Bframes upwards from 3 to 8 had a less than 1/2% improvement in file size. So we can discard that idea.

Each of the other changes improved the file size; yet there was no noticable quality degradation of the Exported video.
Using all optimizations reduced a file size of 85.4 MB to 31.7 MB.

Here is my recommendation, @Stux:

  1. On a short clip, Export using these parameters:
  • 15 frames-per-second
  • Quality = 30%
  • GOP = 300
  1. Try uploading the output to YouTube, to see if the “Processing” software accepts it.
  2. Test your output file with all your players, to see if the are happy with it.
  3. If all these tests pass, Export your main project with these parameters.

Hopefully, this will result in an Export file size you can live with.

YouTube should accept these parameters; they approximate what some laptops produce from the built-in webcam. I doubt YouTube will accept anything less than 15fps.

Cool thanks. I will give it a go.

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Another option is to create a new project with a Video Mode of 240p at 8 frames per second (I think there was some issue with FPS lower than 5), then choose the “Slide Deck (H.264)” export preset. Click the Export > Advanced > Audio tab and change it to whatever settings you feel give equivalent quality to the source file. Leave the other settings as-is. This preset has very aggressive optimizations for video that doesn’t change much, such as, well, PowerPoint slide decks, hence the name. The default audio settings are mono low-bitrate that are good enough for speech but not great for music.

Note: Don’t use hardware encoding with this preset. Also, it’s a little slower at encoding due to its extensive search for repeated frames to compress.

Experiment with a short segment before kicking off a nine hour export!

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I have found that when given settings far outside those of H.264 Main, my Nvidea 710 and/or the associated software says something like “Are you out of your mind? I ain’t doing that!” and leaves the work to the cpu.

Amen and amen!


For my attempts to reduce the file size in such a project, I stayed within the realm where I have experience, or close to that realm.

Will YouTube accept a video with a frame-rate that low?

It should. If it doesn’t, try 12fps. I think I’ve seen surveillance footage uploaded from a 12fps source.

The magic of this preset happens in the Export > Advanced > Other tab, where it changes the reference frame settings, among other things. Most hardware encoders can’t do these things, hence the reason to not use it with this preset.


Thanks everyone, I came back when the notification came through of the first reply:

I took that - followed the process, and made some adjustments, and this is what I came up:

BUT I may try the ultra low frame rate in my next go.

Just about to upload the files and to see how it goes.

Can post images in the third post, 2nd one so far.

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Sometime the simplest method is the best…

ffmpeg -i “image.jpg” -i “audio.mp3” -acodec copy “/tmp/output.mp4”

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