Poor quality encoded MP4 video

Questions involving a Windows version of FFmpeg.
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FrankNatoli
Posts: 6
Joined: Wed Nov 27, 2013 12:09 am

Poor quality encoded MP4 video

Post by FrankNatoli » Tue Oct 10, 2017 6:52 pm

Have adapted FFmpeg muxing.c under Windows 7 to write MP4 files from video camera RGB data.
Using muxing.c default bit_rate=400000.
Am not setting global_quality.
Resultant MP4 is poor quality, highly pixelated.
Original raw images in video camera are sharp.
What values should I use for bit_rate? Do I have to also set rc_max_rate?
What values should I use for global_quality? Do I have to set any flags to enable use of global_quality?
Is bit_rate versus global_quality an either/or situation? Or can both be useful in adjusting quality?
Thanks for your time.

pandy
Posts: 55
Joined: Mon Feb 24, 2014 1:46 pm

Re: Poor quality encoded MP4 video

Post by pandy » Tue Oct 31, 2017 5:01 pm

Sound like you forcing encoder to be 400kbps - perhaps with such bitrate it is unrealistic to expect better quality - not sure as there is very low amount of information in your question.

navilor
Posts: 44
Joined: Thu May 12, 2011 5:19 pm

Re: Poor quality encoded MP4 video

Post by navilor » Sat Nov 11, 2017 10:21 pm

I've been in the streaming media industry since 2008. Use CRF 23 to find your bitrate and then perform a two pass bitrate based encode if you want to stream your content. I wrote a blog post on this very topic.

https://videoblerg.wordpress.com/2017/1 ... -it-wrong/

Neflix uses CRF 23 as the benchmark for their VMAF video analysis tool.

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