To output the codec_type

ffprobe -loglevel error -show_entries stream=codec_type -of default=nw=1 input.foo

Example result:

codec_type=video
codec_type=audio

If you have multiple audio or video streams the output will show multiple video or audio entries.

---

Same as above but output just the values

ffprobe -loglevel error -show_entries stream=codec_type -of default=nw=1=nk=1 input.foo

or:

ffprobe -loglevel error -show_entries stream=codec_type -of csv=p=0 input.foo

Example result:

video
audio

---

To include the stream index

ffprobe -loglevel error -show_entries stream=index,codec_type -of csv=p=0 input.foo

Example result:

0,video
1,audio

In this example the video is the first stream and the audio is the second stream which is the norm but not always the case.

---

Output nothing if there is no audio

ffprobe -loglevel error -select_streams a -show_entries stream=codec_type -of csv=p=0 input.foo

Example result for input with audio:

audio

If the input does not have audio then there will be no output (null output) which could be useful for scripted usage.

---

JSON output example

ffprobe -loglevel error -show_entries stream=codec_type -of json input.mkv 

Example result:

{
    "programs": [

    ],
    "streams": [
        {
            "codec_type": "video"
        },
        {
            "codec_type": "audio"
        }
    ]
}

---

Other output formats

If you want different output formatting (ini, flat, compact, csv, xml) see FFprobe Documentation: Writers.