LibVideo: Add the concept of codec identifiers

This is required for detecting which decoder should be used.
Only a small subset of codecs identifiers is added for now

Userland/Libraries/LibVideo/Containers/Demuxer.h

@@ -8,6 +8,7 @@
 
 #include <AK/NonnullOwnPtr.h>
 #include <LibCore/EventReceiver.h>
+#include <LibVideo/CodecID.h>
 #include <LibVideo/DecoderError.h>
 #include <LibVideo/Sample.h>
 #include <LibVideo/Track.h>
@@ -28,6 +29,8 @@ public:
         return sample.release_nonnull<VideoSample>();
     }
 
+    virtual DecoderErrorOr<CodecID> get_codec_id_for_track(Track track) = 0;
+
     // Returns the timestamp of the keyframe that was seeked to.
     // The value is `Optional` to allow the demuxer to decide not to seek so that it can keep its position
     // in the case that the timestamp is closer to the current time than the nearest keyframe.

Userland/Libraries/LibVideo/Containers/Matroska/MatroskaDemuxer.cpp

@@ -71,6 +71,32 @@ DecoderErrorOr<MatroskaDemuxer::TrackStatus*> MatroskaDemuxer::get_track_status(
     return &m_track_statuses.get(track).release_value();
 }
 
+CodecID MatroskaDemuxer::get_codec_id_for_string(DeprecatedFlyString const& codec_id)
+{
+    dbgln_if(MATROSKA_DEBUG, "Codec ID: {}", codec_id);
+    if (codec_id == "V_VP8")
+        return CodecID::VP8;
+    if (codec_id == "V_VP9")
+        return CodecID::VP9;
+    if (codec_id == "V_MPEG1")
+        return CodecID::MPEG1;
+    if (codec_id == "V_MPEG2")
+        return CodecID::H262;
+    if (codec_id == "V_MPEG4/ISO/AVC")
+        return CodecID::H264;
+    if (codec_id == "V_MPEGH/ISO/HEVC")
+        return CodecID::H265;
+    if (codec_id == "V_AV1")
+        return CodecID::AV1;
+    if (codec_id == "V_THEORA")
+        return CodecID::Theora;
+    if (codec_id == "A_VORBIS")
+        return CodecID::Vorbis;
+    if (codec_id == "A_OPUS")
+        return CodecID::Opus;
+    return CodecID::Unknown;
+}
+
 DecoderErrorOr<Optional<Duration>> MatroskaDemuxer::seek_to_most_recent_keyframe(Track track, Duration timestamp, Optional<Duration> earliest_available_sample)
 {
     // Removing the track status will cause us to start from the beginning.
@@ -119,4 +145,10 @@ DecoderErrorOr<Duration> MatroskaDemuxer::duration()
     return duration.value_or(Duration::zero());
 }
 
+DecoderErrorOr<CodecID> MatroskaDemuxer::get_codec_id_for_track(Track track)
+{
+    auto codec_id = TRY(m_reader.track_for_track_number(track.identifier())).codec_id();
+    return get_codec_id_for_string(codec_id);
+}
+
 }

Userland/Libraries/LibVideo/Containers/Matroska/MatroskaDemuxer.h

@@ -33,6 +33,8 @@ public:
 
     DecoderErrorOr<Duration> duration() override;
 
+    DecoderErrorOr<CodecID> get_codec_id_for_track(Track track) override;
+
 protected:
     DecoderErrorOr<NonnullOwnPtr<Sample>> get_next_sample_for_track(Track track) override;
 
@@ -44,6 +46,7 @@ private:
     };
 
     DecoderErrorOr<TrackStatus*> get_track_status(Track track);
+    CodecID get_codec_id_for_string(DeprecatedFlyString const& codec_id);
 
     Reader m_reader;