Quick start

These steps use the coreav command from Install and two files of your own: an MP4 file, input.mp4, and a Matroska file, input.mkv. Every command exits with status 0 on success.

Describe a file

$ coreav probe input.mp4
{
  "container": {
    "creation_time": null,
    "fragmented": false,
    "major_brand": "isom",
    "timescale": 1000
  },
  ...
  "schema": "coreav.probe/1",
  "streams": [
  ...

coreav probe also reads MOV, Matroska, WebM and MPEG-TS files. A Matroska or WebM file gives coreav.probe-matroska/1, and an MPEG-TS file gives coreav.probe-mpegts/1.

Cut a clip

Cut from the keyframe at or before 1 s up to 3 s, without re-encoding:

coreav clip --start 1 --end 3 input.mp4 clip.mp4

The summary (coreav.clip/1) says where the clip starts after the start time snaps back to a keyframe, and how many samples of each stream it holds.

Remux Matroska to MP4

coreav remux input.mkv output.mp4

The MP4 file has its movie header first (faststart). A stream other than video that MP4 cannot carry is dropped and listed in the summary (coreav.remux/1). A video stream that MP4 cannot carry fails the remux with exit status 1 and no output, unless you add --drop-unsupported (coreav remux).

Check an upload against a policy

A policy is a coreav.policy/1 JSON file. The repository has an example, web-upload.json.

$ coreav check --policy web-upload.json input.mp4
{
  "policy": "web-upload",
  "reasons": [],
  "schema": "coreav.verdict/1",
  "verdict": "accept"
}

Exit status 0 means that the file is accepted, and 1 that it is rejected. The verdict is on standard output in both cases.

Run an ffprobe command line in strict-safe mode

Strict-safe mode is the mode for files you did not make. It runs only what CoreAV implements. For an H.264 file of 320 by 240 pixels with AAC audio, this command prints:

$ coreav --strict-safe ffprobe -v error -show_entries stream=codec_name,width,height -of csv=p=0 input.mp4
h264,320,240
aac

A command line that CoreAV does not implement is refused with exit status 4, and the real ffprobe does not run. Strict-safe mode and the FFmpeg fallback explains both modes.

Next steps

Commands lists every command and its options. coreav --help and coreav COMMAND --help print the same text.
Python shows the same operations from Python.

Get started

Guides

Reference

Project

Describe a file

Cut a clip

Remux Matroska to MP4

Check an upload against a policy

Run an ffprobe command line in strict-safe mode

Next steps

​Describe a file

​Cut a clip

​Remux Matroska to MP4

​Check an upload against a policy

​Run an ffprobe command line in strict-safe mode

​Next steps

Describe a file

Cut a clip

Remux Matroska to MP4

Check an upload against a policy

Run an ffprobe command line in strict-safe mode

Next steps