Add support for Multi-step conversions of media file

[nytamin]

About Me

This pull request is posted on behalf of the NRK.

Type of Contribution

This is a: Feature

New Behavior

This PR adds support for specifying multiple conversion steps for a media file, allowing a user to specify using an external application to perform conversions.

Example of ExpectedPackage:

{
    "packageContainers": {
        "source0": {
            "label": "Source",
            "accessors": {
                "share": {
                    "type": "file_share",
                    "label": "Local",
                    "folderPath": "\\\\MY-SHARE\\source0",
                    "allowRead": true,
                    "allowWrite": false
                }
            }
        },
        "target0": {
            "label": "Target",
            "accessors": {
                "share": {
                    "type": "file_share",
                    "label": "Local",
                    "folderPath": "\\\\MY-SHARE\\target0",
                    "allowRead": true,
                    "allowWrite": true
                }
            }
        }
    },
    "expectedPackages": [
        {
            "type": "media_file",
            "_id": "test_convert",
            "sources": [
                {
                    "containerId": "source0",
                    "accessors": {
                        "share": {
                            "type": "file_share",
                            "filePath": "amb.mp4"
                        }
                    }
                }
            ],
            "contentVersionHash": "abc1234",
            "content": {
                "filePath": "amb.rr"
            },
            "version": {
                "conversions": [
                    {
                        "executable": "ffmpeg.exe",
                        "args": [
                            "-i",
                            "{SOURCE}",
                            "-vf",
                            "scale=640:-1",
                            "-c:a",
                            "copy",
                            "{TARGET}"
                        ],
                        "needsLocalSource": true,
                        "needsLocalTarget": true,
                        "outputFileName": "amb.mp4"
                    },
                    {
                        "executable": "ffmpeg.exe",
                        "args": [
                            "-i",
                            "{SOURCE}",
                            "-vf",
                            "colortemperature=40000",
                            "-c:a",
                            "copy",
                            "{TARGET}"
                        ],
                        "needsLocalSource": true,
                        "needsLocalTarget": true,
                        "outputFileName": "amb.mp4"
                    },
                    {
                        "executable": "ffmpeg.exe",
                        "args": [
                            "-i",
                            "{SOURCE}",
                            "-vf",
                            "rotate=PI/6",
                            "-c:a",
                            "copy",
                            "{TARGET}"
                        ],
                        "needsLocalSource": true,
                        "needsLocalTarget": true,
                        "outputFileName": "amb.mp4"
                    },
                    {
                        "executable": "KairosConverter.exe",
                        "args": [
                            "-i",
                            "{SOURCE}",
                            "-o",
                            "{TARGET}"
                        ],
                        "needsLocalSource": true,
                        "needsLocalTarget": true
                    }
                ]
            },
            
            "layers": [
                "target0"
            ]
        }
    ],
}

Status

• PR is ready to be reviewed.
• The functionality has been tested by the author.
• Relevant unit tests has been added / updated.
• Relevant documentation (code comments, system documentation) has been added / updated.