VLC cannot get length/duration from .ts file

VLC cannot get length/duration from .ts file

If we use function libvlc_media_new_callbacks to create the play media, and then play the video. The VLC cannot get correct length or duration from .ts extension video file, it will display "0";

It works normally with function libvlc_media_new_path.

libvlc_media_new_callbacks is a very useful function that allows users to read .ts video files directly from the memory.

Affected VLC versions:

VLC 3.0

VLC 4.0

Test Code Version:

VLC Library Version: LibVLCSharp.WinForms 3.5.1

VLC Version: 3.0.14

Visual Studio 2019 (C# .net 5.0)

Windows 10 (64 bit)

using LibVLCSharp.Shared;
using LibVLCSharp.WinForms;
using System;
using System.IO;
using System.Windows.Forms;

namespace VideoLengthTest
{
    static class Program
    {
        /// <summary>
        /// Modify the folder where the VLC component is stored
        /// </summary>
        private const string VlcInitPath = @"C:\Program Files\VideoLAN\VLC";

        /// <summary>
        /// Modify the file location of the video that needs to be played
        /// </summary>
        private const string PlayFilePath = @"D:\test-file.ts";

        [STAThread]
        static void Main()
        {
            var form = new Form()
            {
                Width = 800,
                Height = 600,
                StartPosition = FormStartPosition.CenterScreen,
            };

            Core.Initialize(VlcInitPath);
            var libVLC = new LibVLC();

            var player = new VideoView() { Dock = DockStyle.Fill };
            player.MediaPlayer = new MediaPlayer(libVLC);

            form.Shown += (object sender, EventArgs e) =>
            {
                /*
                 * If you change the variable to false, you cannot get the video file length/duration.
                 * If you change the variable to true, you can get the video file length/duration.
                 */
                var useFilePath = false;

                if (useFilePath)
                {
                    player.MediaPlayer.Play(new Media(libVLC, PlayFilePath));
                }
                else
                {
                    player.MediaPlayer.Play(new Media(libVLC, new StreamMediaInput(File.OpenRead(PlayFilePath))));
                }
            };

            form.Controls.Add(player);

            if (true)
            {
                var button = new Button()
                {
                    Text = "Click to get .ts file length/duration",
                    Height = 50,
                    Dock = DockStyle.Top,
                };

                button.Click += (object sender, EventArgs e) =>
                {
                    MessageBox.Show("Get Length:" + player.MediaPlayer.Length);
                };

                form.Controls.Add(button);
            }

            Application.Run(form);
        }
    }
}

I checked the source code and found that after the following modifications, libvlc_media_new_callbacks can return the correct length. This may not be the best solution, but it does make the program return the correct result.

Changed file:

\vlc-3.0.14\modules\demux\mpeg\ts.c

Function name:

static int Demux( demux_t *p_demux )

Code:

if (true)
{
    ts_es_t* p_es = p_pid->u.p_stream->p_es;
    ts_pmt_t* p_pmt = p_es->p_program;

    if (p_pmt->i_last_dts < 1)
    {
        int i_program = 0;
        ProbeEnd(p_demux, i_program);
    }
}

Changed position (picture attachment):