Add FFmpegInputBuilder to support per input options

[Euklios]

Is your feature request related to a problem? Please describe.
We currently don't allow per-input options; therefore, commands requiring multiple inputs aren't supported in many cases.
For example the following command can't be constructed using this library:
ffmpeg -f lavfi -i "testsrc=duration=10:size=1280x720:rate=30" -f lavfi -i "sine=frequency=1000:sample_rate=48000:duration=10" -c:a aac -c:v h264 output.mp4.

Describe the solution you'd like
An FFmpegInputBuilder to construct inputs and allow parameters for individual inputs.

Describe alternatives you've considered
The alternative would be to hack around with addExtraArgs. However, that would undermine the purpose of this library.

Related:

• Support setting input arguments (such as format and bitrate) #17
• Ability to skip defining inputs and do it manually via extra args #65
• order of ExtraArgs #91
• Set input duration #94
• -filter_complex #111
• Incorrect order of arguments for input #124
• [question] different input args for audio and video #156
• Unable to add -safe 0 argument before input #228
• Create WebM DASH Manifest XML file (usually with the extension .mpd) #252
• FFmpegBuilder params order cause error #253
• How to perform screen recorder using this library? #295
• How to create custom inputs arguments. #327
• Add support for -i pipe:0 #334

[Euklios]

This is mainly focused towards fixing EncodingOptions and making it easier to update in the future.
But it should also adding new arguments and flags easier.

[AlexanderSchuetz97]

I am inrested in this too. I currently use addExtraOptions to pass pass input options for decoding rawvideo, like videosize and pixel format.

[Euklios]

@AlexanderSchuetz97 Thank you for the feedback!
If possible, could you share some example commands I can use for tests?

[Euklios]

For anyone interested, I created PR #339 for this feature.

[AlexanderSchuetz97]

i forgot about giving you examples today. Will do so on monday hopefully.

[Euklios]

No problem, any form of help is appreciated

[AlexanderSchuetz97]

These are the 2 Main occurrences of "addExtraArgs" for an Input in the code-base of my current Project.
One is the raw video use case, the other is -strict 2 which I also need for ffprobe.
It allows ffmpeg to decode vvc/h266 videos.

Also FYI, add an option to disable B frames please. (-bf 0)
FFmpeg outputs them by default and 99% of devices that must play the output cannot handle them.

FFmpegBuilder builder = new FFmpegBuilder()
        .addExtraArgs("-video_size", size.getWidth() +"x"+size.getHeight())
        .addExtraArgs("-f", "rawvideo")
        .addExtraArgs("-r", Fraction.getFraction(fps).toString())
        .addExtraArgs("-pix_fmt", "bgr24")
        .addInput("unix://" + socketFile.toAbsolutePath())
        .addOutput(output.getAbsolutePath())
        .addExtraArgs("-bf", "0")
        .setVideoCodec(codec)
        .setFormat(format)
        .disableAudio()
        .done();

FFmpegOutputBuilder builder = mpeg.builder()
        .addExtraArgs("-strict", "-2")
        .addInput(input.getAbsolutePath())
        .addOutput(output.getAbsolutePath())
        .setVideoCodec(videoCodec)
        .setAudioCodec(audioCodec)
        .addExtraArgs("-bf", "0")
        .setFormat(format);

Just FYI This is what I had to do to get your FFProbe to recognize vvc/h266 videos

public class FFProbeWrapper extends FFprobe {

    private static final Map<String, String> VERSION_MAP = new ConcurrentHashMap<>();

    public FFProbeWrapper(@Nonnull String path) throws IOException {
        super(path,new RunProcessFunction() {
            @Override
            public Process run(List<String> args) throws IOException {
                if (args.isEmpty()) {
                    return super.run(args);
                }
                List<String> ar = new ArrayList<>();
                ar.add(args.getFirst());
                ar.add("-strict");
                ar.add("-2");
                ar.addAll(args.subList(1, args.size()));
                return super.run(ar);
            }
        });
    }

    @Nonnull
    @Override
    public synchronized String version() throws IOException {
        String s = VERSION_MAP.get(this.getPath());
        if (s != null) {
            return s;
        }

        String v =  super.version();
        VERSION_MAP.put(this.getPath(), v);
        return v;
    }
}

If you need a H266 testfile I can provide one.

[Euklios]

I've extracted the two issues #345 and #346 based on this.
Strictness -2 matches with experimental, so to my understanding the flag is just not at the right position (on the right builder)