So I have decided to unite in a whole video everything I have of my child. I wanna render it in a sole .mp4 file with 1080p, good audio, etc. I want all that (1:50:00) in 2GB or 3GB, no more. I've seen videos accomplishing this smoothly, but everything I've tried so far ends in 9-12GB.

What I need to do to achieve it?


  • Instead of targeting the final size you should target the bitrate. 1080p at bitrate lower than, say, 5 Mbit/s using AVC encoder would be too low. Not sure why do you care about the file size, the storage in cheap. Unless you plan to put it on a FAT32 memory card.
    – Rusty Core
    Sep 7, 2018 at 3:32

1 Answer 1


I assume you're using the Mainconcept AVC encoder. 3GB for a 1h50m video implies a bitrate of 3.7 mbps. That's the average bitrate you need. Set max bitrate to 5 mbps.

Now, usually I render in two passes. First pass is a high bitrate from Vegas (20 mbps or more) and then encode with ffmpeg, which is a free command line tool.

Command would be

ffmpeg -i vegas.mp4 -crf 23 -movflags +faststart final.mp4

ffmpeg offers lot more variables to adjust but the above should be enough for most size adjustment. Usually a CRF value between 18-28 (lower is better but bigger) works.

  • If Vegas can't produce a small enough H.264 file on its own, it would be better to encode with Vegas to a better mezzanine format than H.264, like DNxHD, ProRes, or even XDCAM/MPEG-2, and then use ffmpeg to convert to H.264. H.264 suffers from very severe concatenation issues that are visible to the average viewer. Dec 19, 2016 at 22:01
  • 'concatenation' issues? I don't follow. My workflow is for output meant for web playout, not broadcast.
    – Gyan
    Dec 20, 2016 at 5:10
  • Concatenation errors occur when you go through multiple encode/decode cycles, particularly of the same codec. I understand that your workflow wasn't for broadcast, but the problems with H.264 are so bad even with just 2 codec cycles, that the average person will notice significant drops in quality. It's no more difficult for the OP to output from Vegas to MPEG-2 and get a much better result. Dec 20, 2016 at 13:57

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