How do I use ffmpeg to get the video resolution?

Question

I am trying to get resolution of the video with the following command:

ffmpeg -i filename.mp4

I get a long output, but I need just the width and height for my bash script. How should I filter out those parameters? Maybe there's a better way to do this.

Answer 1

Use ffprobe

$ ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=s=x:p=0 input.mp4
  1280x720

---

Examples of other output formatting choices

See -of option documentation for more choices and options. Also see FFprobe Tips for other examples including duration and frame rate.

Default

With no [STREAM] wrapper:

$ ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of default=nw=1 input.mp4
  width=1280
  height=720

With no key:

$ ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of default=nw=1:nk=1 input.mp4
  1280
  720

CSV

$ ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=p=0 input.mp4
  1280,720

JSON

$ ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of json input.mp4
{
    "programs": [

    ],
    "streams": [
        {
            "width": 1280,
            "height": 720
        }
    ]
}

XML

$ ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of xml input.mp4
<?xml version="1.0" encoding="UTF-8"?>
<ffprobe>
    <programs>
    </programs>

    <streams>
        <stream width="1280" height="720"/>
    </streams>
</ffprobe>

Answer 2

The following commands rely purely on ffmpeg (and grep and cut) to get you the height or width as required:

Height:

$ ffmpeg -i video.mp4 2>&1 | grep Video: | grep -Po '\d{3,5}x\d{3,5}' | cut -d'x' -f1

1280

Width:

$ ffmpeg -i video.mp4 2>&1 | grep Video: | grep -Po '\d{3,5}x\d{3,5}' | cut -d'x' -f2

720

The difference between the two is just the -f parameter to cut.

If you prefer the full resolution string, you don't need cut:

$ ffmpeg -i video.mp4 2>&1 | grep Video: | grep -Po '\d{3,5}x\d{3,5}'

1280x720

Here's what we're doing with these commands:

1. Running ffmpeg -i to get the file info.
2. Extracting the line which just contains Video: information.
3. Extracting just a string that looks like digitsxdigits which are between 3 and 5 characters.
4. For the first two, cutting out the text before or after the x.

Answer 3

The output of ffprobe looks like this:

streams_stream_0_width=1280
streams_stream_0_height=720

Technically, you can use eval to assign these to bash variables, but this is not necessary and can be unsafe; see here for more:

https://stackoverflow.com/questions/17529220/why-should-eval-be-avoided-in-bash-and-what-should-i-use-instead

Instead, since you are using bash, take advantage of its built-in arrays and string manipulation:

filepath="filename.mp4"
width_prefix='streams_stream_0_width='
height_prefix='streams_stream_0_height='
declare -a dimensions
while read -r line
do
    dimensions+=( "${line}" )
done < <( ffprobe -v error -of flat=s=_ -select_streams v:0 -show_entries stream=width,height "${filepath}" )
width_with_prefix=${dimensions[0]}
height_with_prefix=${dimensions[1]}
width=${width_with_prefix#${width_prefix}}
height=${height_with_prefix#${height_prefix}}
printf "%s\t%sx%s\n" "${filepath}" "${width}" "${height}"

Answer 4

Use grep to select only those lines you are looking for. Redirect the output from STDERR to STDOUT, since ffmpeg will output all info there.

ffmpeg -i filename.mp4 2>&1 | grep <keyword>

Edit: A full working example using perl:

$ ffmpeg -i MVI_7372.AVI 2>&1 | grep Video | perl -wle 'while(<>){ $_ =~ /.*?(\d+x\d+).*/; print $1 }'
640x480

Answer 5

I finally found the answer:

I used this package called Media info

And then I commanded:

mediainfo mediainfo --Inform="Video;%Width%" midhand.mp4

To view the list of params:

mediainfo --Info-Parameters

Best tool to extract video metadata!

Answer 6

I know the question is about bash but, just in case someone ends here looking for a solution for a Windows batch, as myself before I found it out.

for /f "delims=" %%a in ('ffprobe -hide_banner -show_streams filename.mp4 2^>nul ^| findstr "^width= ^height="') do set "myvideo_%%a"

No console messages, and you end with the nice environment variables myvideo_width and myvideo_height. You can check it with:

C:\>set myvideo_
myvideo_height=720
myvideo_width=1280

If the resolution of your video is 1280x720, of course.