CMDT is a CLI tool designed to help video engineers diagnose issues with DASH/HLS manifests and the (mp4) content within! Given a manifest, it will perform the following tasks:

• Parse the manifest
• Download all segments for all renditions (audio, video, thumbnails, captions) to filesystem
• Parse captions from all media files and write to filesystem
• Parse EMSG boxes from all media files and write to filesystem
• Check for CEA caption inconsistencies between video renditions
• Check for gaps between segments
• Run Apple's Media Stream Validator (optionally for HLS)

Pre-built binaries for Linux, Windows, and MacOS are built as part of the release process. The latest release can be found here.

This is a typical node repo, for the most part. Once cloned, run the following:

nvm use
npm i -g pnpm
pnpm i
pnpm build

You must run the full build once before attempting to run the CLI.

At this point, you should be able to run cd cli && pnpm start -h and get the help output from the application.

Options:
  -m, --manifest <string>       Manifest URI. Can also be a local path.
  -o, --output <string>         Output directory (default: "download")
  -s, --skip-download           Skip download (debug)
  -l, --log-level <string>      Log level
  --dash-conformance            Run DASH-IF conformance tool (DASH only)
  -t, --thumbnails              Validate thumbnails (check for duplicates)
  --media-stream-validator      Run apple's media stream validator (HLS only)
  -p, --log-periods             Print a table of periods in manifest (DASH only)
  -h, --help                    display help for command

Typical usage is something like:

pnpm start -m "https://my-site/manifest.mpd" -o output

If you're running a pre-built binary, replace pnpm start with ./cmdt.

After running the tool, all output will be in a directory called output, as specified by the -o option.

The tool will output a large .cmdt file. This is human readable (JSON), but there's a graphical tool that can be helpful for viewing the data.

This tool lives in the 'viewer' directory, but a hosted version can be found here.

type RawReport = {
	missingCues: {
		[representation: RepresentationId]: {
			[cue: string]: Array<RepresentationId>;
		};
	};
	duplicateThumbnails: {
		[representation: RepresentationId]: {
			[thumbnail: string]: Set<RepresentationId>;
		};
	};
    gaps: {
        [mediaType: string]: {
            [representation: string]: Array<{
                expectedStartTime: number;
                previousSegment: Segment;
                segment: Segment;
            }>;
        };
    };
	decodeTimeMismatches: Array<Segment>;
    durationMismatches: Array<Segment>;
	emsgs: {
		[representation: RepresentationId]: {
			segment: Segment;
			emsgs: Array<IEmsg>;
		};
	};
    mediaStreamValidator?: Object;
    dashConformance?: Object;
    manifest: Manifest;
    captions?: {
        [stream: string]: Array<Cue>;
    };
};

export type Manifest = {
	video: Array<Representation>;
	audio: Array<Representation>;
	images: Array<Representation>;
	captionStreamToLanguage: Record<string, string>;
};

For more detailed info on Manifest content, see source.