Easy dotnet DASH.
This library acts as a simplification interface wrapping around ffmpeg and mp4box. Simply pass in a file and the desired qualities, and the complicated commands and output processing is handled for you. The result is a set of media files and an mpd file.
| Package Name | Target Framework | Version |
|---|---|---|
| DEnc | .NET Standard 2.0 |  |
Usage is fairly straightforward. Create a new instance of DEnc.Encoder then call encoder.GenerateDash. Everything has a docstring, but the more esoteric bits are covered below.
You'll need an ffmpeg, ffprobe and mp4box executable on the system you're running from. If you put these in your path variable then the defaults can be left.
You can get executables for your platform here:
These parameters are optional on construction of DEnc.Encoder, but it's highly recommended you provide an action for them. Both callbacks are called to reflect the std output streams for ffmpeg and mp4box. Don't be fooled by the name "stderr", that's actually the logging output for most messages, not just errors. DEnc also writes its own info log entries to this callback.
Qualities are sets of parameters which direct an ffmpeg output stream. You can have several qualities to support DASH adaptive streaming
When you call encoder.GenerateDash a collection of qualities is required. It's important that the collection you provide is distinct on the bitrate, because the bitrate is used in output filenames to ensure they have unique names. Also, it doesn't make much sense to make multiple files at the same bitrate for a DASH encode anyway.
The qualities you give may not be what's actually output. The desired Qualities list is crushed against the input file. Quality crushing happens when you ask for output bitrates higher than the input file bitrate by more than 5%. All bitrates that meet this criteria are removed from the qualities list, and they're replaced by a single copy quality that will mirror the input media exactly, or at least as close as ffmpeg can get it to be. This feature is definitely recommended to save disk space and reduce encode time, but it is optional. Set DisableQualityCrushing to true to disable crushing.
This is supported natively. Simply put vtt files alongside the source file with the same name, and they will be picked up. You can have multiple vtt files by using the naming format file.X.vtt. where X is some string or language code.
For the input file "myvideo.mp4", the following table shows what will be picked up as an external subtitle file.
| Filename | Language | Imported? |
|---|---|---|
| myvideo.mp4 | No, this is the source. | |
| myvideo.srt | No, only vtt is supported. | |
| myvideo.vtt | unk | Yes |
| myvideo.2.vtt | unk | Yes |
| myvideo.subtitleasdf.vtt | unk | Yes |
| myvideo.en.vtt | eng | Yes |
| myvideo.jpn.vtt | jpn | Yes |