Fix exceptions while scanning

Fixes these exceptions:
```
[2019-12-22 20:48:14.779 +01:00] [ERR] Error in WaitForExit
System.InvalidOperationException: No process is associated with this object.
   at System.Diagnostics.Process.EnsureState(State state)
   at System.Diagnostics.Process.EnsureState(State state)
   at System.Diagnostics.Process.GetWaitState()
   at System.Diagnostics.Process.WaitForExitCore(Int32 milliseconds)
   at System.Diagnostics.Process.WaitForExit(Int32 milliseconds)
   at Emby.Server.Implementations.Diagnostics.CommonProcess.WaitForExit(Int32 timeMs) in /home/pi/dev/jellyfin/Emby.Server.Implementations/Diagnostics/CommonProcess.cs:line 100
   at MediaBrowser.MediaEncoding.Encoder.MediaEncoder.StopProcess(ProcessWrapper process, Int32 waitTimeMs) in /home/pi/dev/jellyfin/MediaBrowser.MediaEncoding/Encoder/MediaEncoder.cs:line 785
[2019-12-22 20:48:14.790 +01:00] [INF] Killing ffmpeg process
[2019-12-22 20:48:14.795 +01:00] [ERR] Error killing process
System.InvalidOperationException: No process is associated with this object.
   at System.Diagnostics.Process.EnsureState(State state)
   at System.Diagnostics.Process.EnsureState(State state)
   at System.Diagnostics.Process.Kill()
   at Emby.Server.Implementations.Diagnostics.CommonProcess.Kill() in /home/pi/dev/jellyfin/Emby.Server.Implementations/Diagnostics/CommonProcess.cs:line 95
   at MediaBrowser.MediaEncoding.Encoder.MediaEncoder.StopProcess(ProcessWrapper process, Int32 waitTimeMs) in /home/pi/dev/jellyfin/MediaBrowser.MediaEncoding/Encoder/MediaEncoder.cs:line 799
[2019-12-22 20:48:14.808 +01:00] [ERR] Error in "ffprobe"
System.Text.Json.JsonException: The JSON value could not be converted to System.String. Path: $.streams[0].start_pts | LineNumber: 32 | BytePositionInLine: 26.
 ---> System.InvalidOperationException: Cannot get the value of a token type 'Number' as a string.
   at System.Text.Json.Utf8JsonReader.GetString()
   at System.Text.Json.Serialization.Converters.JsonConverterString.Read(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options)
   at System.Text.Json.JsonPropertyInfoNotNullable`4.OnRead(JsonTokenType tokenType, ReadStack& state, Utf8JsonReader& reader)
   at System.Text.Json.JsonPropertyInfo.Read(JsonTokenType tokenType, ReadStack& state, Utf8JsonReader& reader)
   at System.Text.Json.JsonSerializer.HandleValue(JsonTokenType tokenType, JsonSerializerOptions options, Utf8JsonReader& reader, ReadStack& state)
   at System.Text.Json.JsonSerializer.ReadCore(JsonSerializerOptions options, Utf8JsonReader& reader, ReadStack& readStack)
   --- End of inner exception stack trace ---
   at System.Text.Json.ThrowHelper.ReThrowWithPath(ReadStack& readStack, Utf8JsonReader& reader, Exception ex)
   at System.Text.Json.JsonSerializer.ReadCore(JsonSerializerOptions options, Utf8JsonReader& reader, ReadStack& readStack)
   at System.Text.Json.JsonSerializer.ReadCore(JsonReaderState& readerState, Boolean isFinalBlock, ReadOnlySpan`1 buffer, JsonSerializerOptions options, ReadStack& readStack)
   at System.Text.Json.JsonSerializer.ReadAsync[TValue](Stream utf8Json, Type returnType, JsonSerializerOptions options, CancellationToken cancellationToken)
   at MediaBrowser.MediaEncoding.Encoder.MediaEncoder.GetMediaInfoInternal(String inputPath, String primaryPath, MediaProtocol protocol, Boolean extractChapters, String probeSizeArgument, Boolean isAudio, Nullable`1 videoType, Boolean forceEnableLogging, CancellationToken cancellationToken) in /home/pi/dev/jellyfin/MediaBrowser.MediaEncoding/Encoder/MediaEncoder.cs:line 399
   at MediaBrowser.Providers.MediaInfo.FFProbeVideoInfo.ProbeVideo[T](T item, MetadataRefreshOptions options, CancellationToken cancellationToken) in /home/pi/dev/jellyfin/MediaBrowser.Providers/MediaInfo/FFProbeVideoInfo.cs:line 122
   at MediaBrowser.Providers.Manager.MetadataService`2.RunCustomProvider(ICustomMetadataProvider`1 provider, TItemType item, String logName, MetadataRefreshOptions options, RefreshResult refreshResult, CancellationToken cancellationToken) in /home/pi/dev/jellyfin/MediaBrowser.Providers/Manager/MetadataService.cs:line 815
```

1 files changed, 81 insertions, 0 deletions

diff --git a/MediaBrowser.MediaEncoding/Probing/MediaFormatInfo.cs b/MediaBrowser.MediaEncoding/Probing/MediaFormatInfo.cs
new file mode 100644
index 000000000..d5529e56c
--- /dev/null
+++ b/MediaBrowser.MediaEncoding/Probing/MediaFormatInfo.cs
@@ -0,0 +1,81 @@
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
+namespace MediaBrowser.MediaEncoding.Probing
+{
+    /// <summary>
+    /// Class MediaFormat.
+    /// </summary>
+    public class MediaFormatInfo
+    {
+        /// <summary>
+        /// Gets or sets the filename.
+        /// </summary>
+        /// <value>The filename.</value>
+        [JsonPropertyName("filename")]
+        public string Fileame { get; set; }
+
+        /// <summary>
+        /// Gets or sets the nb_streams.
+        /// </summary>
+        /// <value>The nb_streams.</value>
+        [JsonPropertyName("nb_streams")]
+        public int NbStreams { get; set; }
+
+        /// <summary>
+        /// Gets or sets the format_name.
+        /// </summary>
+        /// <value>The format_name.</value>
+        [JsonPropertyName("format_name")]
+        public string FormatName { get; set; }
+
+        /// <summary>
+        /// Gets or sets the format_long_name.
+        /// </summary>
+        /// <value>The format_long_name.</value>
+        [JsonPropertyName("format_long_name")]
+        public string FormatLongName { get; set; }
+
+        /// <summary>
+        /// Gets or sets the start_time.
+        /// </summary>
+        /// <value>The start_time.</value>
+        [JsonPropertyName("start_time")]
+        public string StartTime { get; set; }
+
+        /// <summary>
+        /// Gets or sets the duration.
+        /// </summary>
+        /// <value>The duration.</value>
+        [JsonPropertyName("duration")]
+        public string Duration { get; set; }
+
+        /// <summary>
+        /// Gets or sets the size.
+        /// </summary>
+        /// <value>The size.</value>
+        [JsonPropertyName("size")]
+        public string Size { get; set; }
+
+        /// <summary>
+        /// Gets or sets the bit_rate.
+        /// </summary>
+        /// <value>The bit_rate.</value>
+        [JsonPropertyName("bit_rate")]
+        public string BitRate { get; set; }
+
+        /// <summary>
+        /// Gets or sets the probe_score.
+        /// </summary>
+        /// <value>The probe_score.</value>
+        [JsonPropertyName("probe_score")]
+        public int ProbeScore { get; set; }
+
+        /// <summary>
+        /// Gets or sets the tags.
+        /// </summary>
+        /// <value>The tags.</value>
+        [JsonPropertyName("tags")]
+        public IReadOnlyDictionary<string, string> Tags { get; set; }
+    }
+}