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, 282 insertions, 0 deletions

diff --git a/MediaBrowser.MediaEncoding/Probing/MediaStreamInfo.cs b/MediaBrowser.MediaEncoding/Probing/MediaStreamInfo.cs
new file mode 100644
index 000000000..7fa7afa5b
--- /dev/null
+++ b/MediaBrowser.MediaEncoding/Probing/MediaStreamInfo.cs
@@ -0,0 +1,282 @@
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+using MediaBrowser.Common.Json.Converters;
+
+namespace MediaBrowser.MediaEncoding.Probing
+{
+    /// <summary>
+    /// Represents a stream within the output.
+    /// </summary>
+    public class MediaStreamInfo
+    {
+        /// <summary>
+        /// Gets or sets the index.
+        /// </summary>
+        /// <value>The index.</value>
+        [JsonPropertyName("index")]
+        public int Index { get; set; }
+
+        /// <summary>
+        /// Gets or sets the profile.
+        /// </summary>
+        /// <value>The profile.</value>
+        [JsonPropertyName("profile")]
+        public string Profile { get; set; }
+
+        /// <summary>
+        /// Gets or sets the codec_name.
+        /// </summary>
+        /// <value>The codec_name.</value>
+        [JsonPropertyName("codec_name")]
+        public string CodecName { get; set; }
+
+        /// <summary>
+        /// Gets or sets the codec_long_name.
+        /// </summary>
+        /// <value>The codec_long_name.</value>
+        [JsonPropertyName("codec_long_name")]
+        public string CodecLongName { get; set; }
+
+        /// <summary>
+        /// Gets or sets the codec_type.
+        /// </summary>
+        /// <value>The codec_type.</value>
+        [JsonPropertyName("codec_type")]
+        public string CodecType { get; set; }
+
+        /// <summary>
+        /// Gets or sets the sample_rate.
+        /// </summary>
+        /// <value>The sample_rate.</value>
+        [JsonPropertyName("sample_rate")]
+        public string SampleRate { get; set; }
+
+        /// <summary>
+        /// Gets or sets the channels.
+        /// </summary>
+        /// <value>The channels.</value>
+        [JsonPropertyName("channels")]
+        public int Channels { get; set; }
+
+        /// <summary>
+        /// Gets or sets the channel_layout.
+        /// </summary>
+        /// <value>The channel_layout.</value>
+        [JsonPropertyName("channel_layout")]
+        public string ChannelLayout { get; set; }
+
+        /// <summary>
+        /// Gets or sets the avg_frame_rate.
+        /// </summary>
+        /// <value>The avg_frame_rate.</value>
+        [JsonPropertyName("avg_frame_rate")]
+        public string AverageFrameRate { 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 bit_rate.
+        /// </summary>
+        /// <value>The bit_rate.</value>
+        [JsonPropertyName("bit_rate")]
+        public string BitRate { get; set; }
+
+        /// <summary>
+        /// Gets or sets the width.
+        /// </summary>
+        /// <value>The width.</value>
+        [JsonPropertyName("width")]
+        public int Width { get; set; }
+
+        /// <summary>
+        /// Gets or sets the refs.
+        /// </summary>
+        /// <value>The refs.</value>
+        [JsonPropertyName("refs")]
+        public int Refs { get; set; }
+
+        /// <summary>
+        /// Gets or sets the height.
+        /// </summary>
+        /// <value>The height.</value>
+        [JsonPropertyName("height")]
+        public int Height { get; set; }
+
+        /// <summary>
+        /// Gets or sets the display_aspect_ratio.
+        /// </summary>
+        /// <value>The display_aspect_ratio.</value>
+        [JsonPropertyName("display_aspect_ratio")]
+        public string DisplayAspectRatio { get; set; }
+
+        /// <summary>
+        /// Gets or sets the tags.
+        /// </summary>
+        /// <value>The tags.</value>
+        [JsonPropertyName("tags")]
+        public IReadOnlyDictionary<string, string> Tags { get; set; }
+
+        /// <summary>
+        /// Gets or sets the bits_per_sample.
+        /// </summary>
+        /// <value>The bits_per_sample.</value>
+        [JsonPropertyName("bits_per_sample")]
+        public int BitsPerSample { get; set; }
+
+        /// <summary>
+        /// Gets or sets the bits_per_raw_sample.
+        /// </summary>
+        /// <value>The bits_per_raw_sample.</value>
+        [JsonPropertyName("bits_per_raw_sample")]
+        [JsonConverter(typeof(JsonInt32Converter))]
+        public int BitsPerRawSample { get; set; }
+
+        /// <summary>
+        /// Gets or sets the r_frame_rate.
+        /// </summary>
+        /// <value>The r_frame_rate.</value>
+        [JsonPropertyName("r_frame_rate")]
+        public string RFrameRate { get; set; }
+
+        /// <summary>
+        /// Gets or sets the has_b_frames.
+        /// </summary>
+        /// <value>The has_b_frames.</value>
+        [JsonPropertyName("has_b_frames")]
+        public int HasBFrames { get; set; }
+
+        /// <summary>
+        /// Gets or sets the sample_aspect_ratio.
+        /// </summary>
+        /// <value>The sample_aspect_ratio.</value>
+        [JsonPropertyName("sample_aspect_ratio")]
+        public string SampleAspectRatio { get; set; }
+
+        /// <summary>
+        /// Gets or sets the pix_fmt.
+        /// </summary>
+        /// <value>The pix_fmt.</value>
+        [JsonPropertyName("pix_fmt")]
+        public string PixelFormat { get; set; }
+
+        /// <summary>
+        /// Gets or sets the level.
+        /// </summary>
+        /// <value>The level.</value>
+        [JsonPropertyName("level")]
+        public int Level { get; set; }
+
+        /// <summary>
+        /// Gets or sets the time_base.
+        /// </summary>
+        /// <value>The time_base.</value>
+        [JsonPropertyName("time_base")]
+        public string TimeBase { 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 codec_time_base.
+        /// </summary>
+        /// <value>The codec_time_base.</value>
+        [JsonPropertyName("codec_time_base")]
+        public string CodecTimeBase { get; set; }
+
+        /// <summary>
+        /// Gets or sets the codec_tag.
+        /// </summary>
+        /// <value>The codec_tag.</value>
+        [JsonPropertyName("codec_tag")]
+        public string CodecTag { get; set; }
+
+        /// <summary>
+        /// Gets or sets the codec_tag_string.
+        /// </summary>
+        /// <value>The codec_tag_string.</value>
+        [JsonPropertyName("codec_tag_string")]
+        public string CodecTagString { get; set; }
+
+        /// <summary>
+        /// Gets or sets the sample_fmt.
+        /// </summary>
+        /// <value>The sample_fmt.</value>
+        [JsonPropertyName("sample_fmt")]
+        public string SampleFmt { get; set; }
+
+        /// <summary>
+        /// Gets or sets the dmix_mode.
+        /// </summary>
+        /// <value>The dmix_mode.</value>
+        [JsonPropertyName("dmix_mode")]
+        public string DmixMode { get; set; }
+
+        /// <summary>
+        /// Gets or sets the start_pts.
+        /// </summary>
+        /// <value>The start_pts.</value>
+        [JsonPropertyName("start_pts")]
+        public int StartPts { get; set; }
+
+        /// <summary>
+        /// Gets or sets the is_avc.
+        /// </summary>
+        /// <value>The is_avc.</value>
+        [JsonPropertyName("is_avc")]
+        public string IsAvc { get; set; }
+
+        /// <summary>
+        /// Gets or sets the nal_length_size.
+        /// </summary>
+        /// <value>The nal_length_size.</value>
+        [JsonPropertyName("nal_length_size")]
+        public string NalLengthSize { get; set; }
+
+        /// <summary>
+        /// Gets or sets the ltrt_cmixlev.
+        /// </summary>
+        /// <value>The ltrt_cmixlev.</value>
+        [JsonPropertyName("ltrt_cmixlev")]
+        public string LtrtCmixlev { get; set; }
+
+        /// <summary>
+        /// Gets or sets the ltrt_surmixlev.
+        /// </summary>
+        /// <value>The ltrt_surmixlev.</value>
+        [JsonPropertyName("ltrt_surmixlev")]
+        public string LtrtSurmixlev { get; set; }
+
+        /// <summary>
+        /// Gets or sets the loro_cmixlev.
+        /// </summary>
+        /// <value>The loro_cmixlev.</value>
+        [JsonPropertyName("loro_cmixlev")]
+        public string LoroCmixlev { get; set; }
+
+        /// <summary>
+        /// Gets or sets the loro_surmixlev.
+        /// </summary>
+        /// <value>The loro_surmixlev.</value>
+        [JsonPropertyName("loro_surmixlev")]
+        public string LoroSurmixlev { get; set; }
+
+        [JsonPropertyName("field_order")]
+        public string FieldOrder { get; set; }
+
+        /// <summary>
+        /// Gets or sets the disposition.
+        /// </summary>
+        /// <value>The disposition.</value>
+        [JsonPropertyName("disposition")]
+        public IReadOnlyDictionary<string, int> Disposition { get; set; }
+    }
+}