CloudMusic/FNZCM2/FNZCM2.ProofOfConcept/PocFFMPEG.cs

using FFmpeg.AutoGen;
using System.IO.Enumeration;
using System.Runtime.InteropServices;
using System.Text;

namespace FNZCM2.ProofOfConcept;

using FSE = (bool isDir, string path, long size, DateTimeOffset lastWrited);


internal static class PocFFMPEG
{
    public static unsafe void RunPoc()
    {
        //BEGIN init once
        ffmpeg.RootPath = "./libFFMPEG/bin";

        var tryAllocateFormatContext = ffmpeg.avformat_alloc_context();
        if(tryAllocateFormatContext!=null) ffmpeg.avformat_free_context(tryAllocateFormatContext);

        //DynamicallyLoadedBindings.Initialize();
        //ffmpeg.avdevice_register_all();
        //END init once

        //choose a file to open
        var fse = new FileSystemEnumerable<FSE>(
            "library",
            (ref FileSystemEntry p) => new(
                p.IsDirectory,
                p.ToFullPath(),
                p.Length,
                p.LastWriteTimeUtc
            ),
            new()
            {
                RecurseSubdirectories = true,
            })
        {
            ShouldIncludePredicate = (ref FileSystemEntry p) => p.ToFullPath().EndsWith(".flac", true, null)
        };

        var file = fse.First();
        var filePath = file.path;

        //BEGIN session
        var formatContext = ffmpeg.avformat_alloc_context();
        if (0 != ffmpeg.avformat_open_input(&formatContext, filePath, null, null))
        {
            throw new Exception("Could not open file.");
        }

        if (ffmpeg.avformat_find_stream_info(formatContext, null) != 0)
        {
            throw new Exception("Could not retrieve stream info.");
        }

        Dictionary<string, string> tags = new();

        AVDictionaryEntry* tag = null;
        while ((tag = ffmpeg.av_dict_get(formatContext->metadata, "", tag, 0)) != null)
        {
            var k = Marshal.PtrToStringUTF8((IntPtr)tag->key);
            var v = Marshal.PtrToStringUTF8((IntPtr)tag->value);

            if (tags.ContainsKey(k))
            {
                int bp = 0;
            }

            tags[k] = v;
        }

        {
            var f = formatContext->iformat;
            var ln = Marshal.PtrToStringUTF8((IntPtr)f->long_name);
            var n = Marshal.PtrToStringUTF8((IntPtr)f->name);
            

        }


        for (int i = 0; i < formatContext->nb_streams; i++)
        {
            var stream = formatContext->streams[i];

            var codec = ffmpeg.avcodec_find_decoder(stream->codecpar->codec_id);
            var codecName = codec != null ? ffmpeg.avcodec_get_name(stream->codecpar->codec_id) : "Unknown codec";
            var codeType = stream->codecpar->codec_type;



            if (stream->disposition == ffmpeg.AV_DISPOSITION_ATTACHED_PIC)
            {
                var pkt = stream->attached_pic;
                //Console.WriteLine($"Embedded cover art: Size={pkt.size} bytes, Format={ffmpeg.avcodec_get_name(pkt.)}");
            }
        }

        ffmpeg.avformat_close_input(&formatContext);
        //END session


        //SUCCESS
    }
}