CODEWITHSUNDEEP
videoffmpegvideo-processing
bozzmob
bozzmob

Reputation: 12574

Losing video quality during ffmpeg filter_complex

My input video is of dimension 720x1280. The output I am getting from the command below is 1920x1080.

The problem that I am facing is, a good 720p video is losing its quality and the output video is deteriorated.

ffmpeg -i inter.mpg -filter_complex "[0]scale=hd1080,setsar=1,boxblur=20:20[b]; [0]scale=-1:1080[v];[b][v]overlay=(W-w)/2" inter_1920x1080.mpg

I am ok to scale up my video size to match the 1280 height if downsizing the height is causing the issue. But, is there a way to add custom value to the 'scale'?

Ref: I have referred to this answer from Gyan.

I tried with the following command now-

ffmpeg -i 6691602248444677381.mp4 -c:v -filter_complex "[0]scale=hd1080,setsar=1,boxblur=20:20[b]; [0]scale=-1:1080[v];[b][v]overlay=(W-w)/2" -b:v 800k output.mp4

I am getting the following error -

[NULL @ 0x7fa2af800000] Unable to find a suitable output format for '[0]scale=hd1080,setsar=1,boxblur=20:20[b]; [0]scale=-1:1080[v];[b][v]overlay=(W-w)/2'
[0]scale=hd1080,setsar=1,boxblur=20:20[b]; [0]scale=-1:1080[v];[b][v]overlay=(W-w)/2: Invalid argument

Upvotes: 2

Views: 1932

Answers (1)

llogan
llogan

Reputation: 133813

Question 1: .mpg quality is bad

You are using the encoder mpeg1video, the default for .mpg, which outputs a very old, legacy format (MPEG-1 Video). The default bitrate value for this ancient encoder is not sufficient for modern sized videos. If this is the format that you want then add the output option -q:v 3. Increase the value for less quality. Or choose a bitrate such as -b:v 8000k (that's just an arbitrary bitrate value for demonstration purposes).

If MPEG-1 is not the format you want then use the -c:v option to choose your desired encoder, and/or change the output container format (such as .mkv or .mp4).

Example:

ffmpeg -i inter.mpg -filter_complex "[0]scale=hd1080,setsar=1,boxblur=20:20[b]; [0]scale=-1:1080[v];[b][v]overlay=(W-w)/2" -c:v mpeg2video -q:v 3 inter_1920x1080.mpg

Question 2: Unable to find a suitable output format for [0]scale=hd1080...

You added -c:v but did not provide an actual value, so it is assuming your filtergraph is the name of the encoder you want to use. A correct example is -c:v libx264.

You are now using .mp4 so just omit -c:v because it will choose a sane default encoder which will be libx264. This encoder outputs H.264 video.

libx264 also has a sane bitrate default, so remove -b:v 800k.

Your command should now look like:

ffmpeg -i 6691602248444677381.mp4 -filter_complex "[0]scale=hd1080,setsar=1,boxblur=20:20[b]; [0]scale=-1:1080[v];[b][v]overlay=(W-w)/2" output.mp4

Upvotes: 2

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