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I have high resolution video

  Duration: 00:06:28.80, start: 0.000000, bitrate: 15968 kb/s
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 15809 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc (default)
    Metadata:
      creation_time   : 2016-10-11 05:35:02
      handler_name    : Alias Data Handler
      encoder         : AVC Coding
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 157 kb/s (default)
    Metadata:
      creation_time   : 2016-10-11 05:35:02
      handler_name    : Alias Data Handler

Its 6+min video.

I am ok with resolution of 240p (because i want to send it on whatsapp)

In order my video to look good quality what is the recommended bitrate for 240p. Also is what is the minimum bitrate below which the chances of pixelating will be there in the video.

I dont want to go for high bitrate also. Because ultimately i want the size to be not more than 240p.

I use mpv to see the video. I scale the original video to 240p, the quality after conversion should match the quality visible in mpv. That will give me first hand idea of how good is the conversion.

I expect a good amount of reduction in size(MB : where original is 740mb) of the file when reduced from 1920x1080 to 240p

I have found some information regarding this.

enter image description here

How much is this true

Santhosh
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  • This question is asking wrt to the resolution 240p, 360p etc. – Santhosh Oct 14 '16 at 13:09
  • The answer remains the same. – llogan Oct 14 '16 at 16:31
  • see the edited question. I have found some info on a website.It suggests some resolution vs bitrate values. Ofcourse he is mentioning for some of his live streaming cameras. But is it closer that quality is approximately good with the values – Santhosh Oct 15 '16 at 06:00
  • Also i prefer to use two pass so that i can get the required bitrate. in crf we have to wait to see what will be the final bitrate. Or is there a way to check with crf, to the know the bitrate – Santhosh Oct 15 '16 at 06:02
  • Why is choosing a specific bitrate so important? The bitrate to achieve an acceptable quality will vary depending on the complexity of your input, the encoder you want to use, and your subjective definition of an acceptable quality level. – llogan Oct 15 '16 at 06:22
  • Ok. Then will not worry about bitrate. I am trying the following as per the solution suggested. `ffmpeg -ss 30 -i input -t 60 -codec:v libx264 -preset medium -crf 24 -vf scale=-2:240 -codec:a copy outputmp4` . So this will first reduce the resolution to 240 and then encode using crf 24 or both act simultaneously or scaling does not matter at. – Santhosh Oct 15 '16 at 06:33
  • It does not matter if scale is before or after crf. Because you are encoding, and not just re-muxing, the input will be completely decoded to raw video regardless if you're filtering or not: see [flowchart](https://ffmpeg.org/ffmpeg.html#Detailed-description). – llogan Oct 15 '16 at 17:18

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