matroska part 1

4 files changed, 347 insertions, 325 deletions

diff --git a/ebml/src/bin/experiment.rs b/ebml/src/bin/experiment.rs
index d332b41..13b6895 100644
--- a/ebml/src/bin/experiment.rs
+++ b/ebml/src/bin/experiment.rs
@@ -1,12 +1,12 @@
-use std::fs::File;
 use ebml::read::EbmlReader;
+use std::{fs::File, io::BufReader};
 
 fn main() {
     env_logger::init_from_env("LOG");
     let f = File::open(std::env::args().skip(1).next().unwrap()).unwrap();
-    let mut r = EbmlReader::new(f);
+    let mut r = EbmlReader::new(BufReader::new(f));
 
     loop {
-        println!("{:?}", r.read_tag().unwrap());
+        println!("{:?}", r.read_tag());
     }
 }
diff --git a/ebml/src/lib.rs b/ebml/src/lib.rs
index acebae3..7445bbc 100644
--- a/ebml/src/lib.rs
+++ b/ebml/src/lib.rs
@@ -1,8 +1,4 @@
-use crate::read::EbmlSize;
-
-use self::read::EbmlReader;
-use anyhow::{bail, Result};
-use log::debug;
+use anyhow::bail;
 
 pub mod matroska;
 pub mod read;
@@ -14,53 +10,28 @@ pub enum Master {
     End,
 }
 
-#[derive(Debug, Clone)]
-pub enum MatroskaTag {
-    Ebml(Master),
-    EbmlVersion(u64),
-    EbmlReadVersion(u64),
-    EbmlMaxIdLength(u64),
-    EbmlMaxSizeLength(u64),
-    DocType(String),
-    DocTypeVersion(u64),
-    DocTypeReadVersion(u64),
-    DocTypeExtension(Master),
-}
-
-impl EbmlReader {
-    pub fn read_tag(&mut self) -> Result<MatroskaTag> {
-        let id = self.read_tag_id()?;
-        let size = EbmlSize::from_vint(self.read_vint_len()?);
-        debug!("tag id={id:x}, size={size:?}");
-        Ok(match id {
-            0x1a45dfa3 => MatroskaTag::Ebml(Master::Start),
-            0x4286 => MatroskaTag::EbmlVersion(self.read_vint()?),
-            0x42f7 => MatroskaTag::EbmlReadVersion(self.read_vint()?),
-            0x42f2 => MatroskaTag::EbmlMaxIdLength(self.read_vint()?),
-            0x42f3 => MatroskaTag::EbmlMaxSizeLength(self.read_vint()?),
-            0x4282 => MatroskaTag::DocType(self.read_utf8(size)?),
-            0x4287 => MatroskaTag::DocTypeVersion(self.read_vint()?),
-            0x4285 => MatroskaTag::DocTypeReadVersion(self.read_vint()?),
-            0x4281 => MatroskaTag::DocTypeExtension(Master::Start),
-
-            _ => bail!("thats not a tag we know..."),
-        })
-    }
-}
-
 pub trait ValueFromBuf: Sized {
     fn from_buf(buf: &[u8]) -> anyhow::Result<Self>;
 }
 
 impl ValueFromBuf for u64 {
     fn from_buf(buf: &[u8]) -> anyhow::Result<Self> {
-        if buf.len() != 8 {
-            bail!("u64 is not 64 bits long")
+        // if buf.len() != 8 {
+        //     bail!("u64 is not 64 bits long")
+        // }
+        // Ok((buf[0] as u64) << 24
+        //     | (buf[1] as u64) << 16
+        //     | (buf[2] as u64) << 8
+        //     | (buf[3] as u64) << 0)
+        if buf.len() > 8 {
+            bail!("u64 too big")
+        }
+        let mut val = 0u64;
+        for byte in buf {
+            val <<= 8;
+            val |= *byte as u64;
         }
-        Ok((buf[0] as u64) << 24
-            | (buf[1] as u64) << 16
-            | (buf[2] as u64) << 8
-            | (buf[3] as u64) << 0)
+        Ok(val)
     }
 }
 impl ValueFromBuf for Vec<u8> {
@@ -73,8 +44,3 @@ impl ValueFromBuf for String {
         Ok(String::from_utf8(Vec::from(buf))?)
     }
 }
-impl ValueFromBuf for Master {
-    fn from_buf(_buf: &[u8]) -> anyhow::Result<Self> {
-        Ok(Master::Start)
-    }
-}
diff --git a/ebml/src/matroska.rs b/ebml/src/matroska.rs
index 966530c..c9198bb 100644
--- a/ebml/src/matroska.rs
+++ b/ebml/src/matroska.rs
@@ -17,266 +17,313 @@ define_ebml! {
             DocTypeExtensionVersion[0x4284]: Uint,
         },
     },
-}
 
-//   #[id=0x18538067] Segment(Master),
-//   #[id=0x1941A469] Segment/Attachments(Master),
-//   #[id=0x61A7] Segment/Attachments/AttachedFile(Master),
-//   #[id=0x465C] Segment/Attachments/AttachedFile/FileData(Vec<u8>),
-//   #[id=0x467E] Segment/Attachments/AttachedFile/FileDescription(Utf8),
-//   #[id=0x4660] Segment/Attachments/AttachedFile/FileMimeType(Utf8),
-//   #[id=0x466E] Segment/Attachments/AttachedFile/FileName(Utf8),
-//   #[id=0x4675] Segment/Attachments/AttachedFile/FileReferral(Vec<u8>),
-//   #[id=0x46AE] Segment/Attachments/AttachedFile/FileUID(Uint),
-//   #[id=0x4662] Segment/Attachments/AttachedFile/FileUsedEndTime(Uint),
-//   #[id=0x4661] Segment/Attachments/AttachedFile/FileUsedStartTime(Uint),
-
-//   #[id=0x1043A770] Segment/Chapters(Master),
-//   #[id=0x45B9] Segment/Chapters/EditionEntry(Master),
-//   #[id=0xB6] Segment/Chapters/EditionEntry/ChapterAtom(Master),
-//   #[id=0x6944] Segment/Chapters/EditionEntry/ChapterAtom/ChapProcess(Master),
-//   #[id=0x6955] Segment/Chapters/EditionEntry/ChapterAtom/ChapProcess/ChapProcessCodecID(Uint),
-//   #[id=0x6911] Segment/Chapters/EditionEntry/ChapterAtom/ChapProcess/ChapProcessCommand(Master),
-//   #[id=0x6933] Segment/Chapters/EditionEntry/ChapterAtom/ChapProcess/ChapProcessCommand/ChapProcessData(Vec<u8>),
-//   #[id=0x6922] Segment/Chapters/EditionEntry/ChapterAtom/ChapProcess/ChapProcessCommand/ChapProcessTime(Uint),
-//   #[id=0x450D] Segment/Chapters/EditionEntry/ChapterAtom/ChapProcess/ChapProcessPrivate(Vec<u8>),
-//   #[id=0x80] Segment/Chapters/EditionEntry/ChapterAtom/ChapterDisplay(Master),
-//   #[id=0x437E] Segment/Chapters/EditionEntry/ChapterAtom/ChapterDisplay/ChapCountry(Utf8),
-//   #[id=0x437C] Segment/Chapters/EditionEntry/ChapterAtom/ChapterDisplay/ChapLanguage(Utf8),
-//   #[id=0x437D] Segment/Chapters/EditionEntry/ChapterAtom/ChapterDisplay/ChapLanguageIETF(Utf8),
-//   #[id=0x85] Segment/Chapters/EditionEntry/ChapterAtom/ChapterDisplay/ChapString(Utf8),
-//   #[id=0x4598] Segment/Chapters/EditionEntry/ChapterAtom/ChapterFlagEnabled(Uint),
-//   #[id=0x98] Segment/Chapters/EditionEntry/ChapterAtom/ChapterFlagHidden(Uint),
-//   #[id=0x63C3] Segment/Chapters/EditionEntry/ChapterAtom/ChapterPhysicalEquiv(Uint),
-//   #[id=0x6EBC] Segment/Chapters/EditionEntry/ChapterAtom/ChapterSegmentEditionUID(Uint),
-//   #[id=0x6E67] Segment/Chapters/EditionEntry/ChapterAtom/ChapterSegmentUID(Vec<u8>),
-//   #[id=0x5654] Segment/Chapters/EditionEntry/ChapterAtom/ChapterStringUID(Utf8),
-//   #[id=0x92] Segment/Chapters/EditionEntry/ChapterAtom/ChapterTimeEnd(Uint),
-//   #[id=0x91] Segment/Chapters/EditionEntry/ChapterAtom/ChapterTimeStart(Uint),
-//   #[id=0x8F] Segment/Chapters/EditionEntry/ChapterAtom/ChapterTrack(Master),
-//   #[id=0x89] Segment/Chapters/EditionEntry/ChapterAtom/ChapterTrack/ChapterTrackUID(Uint),
-//   #[id=0x73C4] Segment/Chapters/EditionEntry/ChapterAtom/ChapterUID(Uint),
-//   #[id=0x45DB] Segment/Chapters/EditionEntry/EditionFlagDefault(Uint),
-//   #[id=0x45BD] Segment/Chapters/EditionEntry/EditionFlagHidden(Uint),
-//   #[id=0x45DD] Segment/Chapters/EditionEntry/EditionFlagOrdered(Uint),
-//   #[id=0x45BC] Segment/Chapters/EditionEntry/EditionUID(Uint),
-
-//   #[id=0x1F43B675] Segment/Cluster(Master),
-//   #[id=0xA0] Segment/Cluster/BlockGroup(Master),
-//   #[id=0xA1] Segment/Cluster/BlockGroup/Block(Vec<u8>),
-//   #[id=0x75A1] Segment/Cluster/BlockGroup/BlockAdditions(Master),
-//   #[id=0xA6] Segment/Cluster/BlockGroup/BlockAdditions/BlockMore(Master),
-//   #[id=0xEE] Segment/Cluster/BlockGroup/BlockAdditions/BlockMore/BlockAddID(Uint),
-//   #[id=0xA5] Segment/Cluster/BlockGroup/BlockAdditions/BlockMore/BlockAdditional(Vec<u8>),
-//   #[id=0x9B] Segment/Cluster/BlockGroup/BlockDuration(Uint),
-//   #[id=0xA2] Segment/Cluster/BlockGroup/BlockVirtual(Vec<u8>),
-//   #[id=0xA4] Segment/Cluster/BlockGroup/CodecState(Vec<u8>),
-//   #[id=0x75A2] Segment/Cluster/BlockGroup/DiscardPadding(Integer),
-//   #[id=0xFB] Segment/Cluster/BlockGroup/ReferenceBlock(Integer),
-//   #[id=0xC8] Segment/Cluster/BlockGroup/ReferenceFrame(Master),
-//   #[id=0xC9] Segment/Cluster/BlockGroup/ReferenceFrame/ReferenceOffset(Uint),
-//   #[id=0xCA] Segment/Cluster/BlockGroup/ReferenceFrame/ReferenceTimestamp(Uint),
-//   #[id=0xFA] Segment/Cluster/BlockGroup/ReferencePriority(Uint),
-//   #[id=0xFD] Segment/Cluster/BlockGroup/ReferenceVirtual(Integer),
-//   #[id=0x8E] Segment/Cluster/BlockGroup/Slices(Master),
-//   #[id=0xE8] Segment/Cluster/BlockGroup/Slices/TimeSlice(Master),
-//   #[id=0xCB] Segment/Cluster/BlockGroup/Slices/TimeSlice/BlockAdditionID(Uint),
-//   #[id=0xCE] Segment/Cluster/BlockGroup/Slices/TimeSlice/Delay(Uint),
-//   #[id=0xCD] Segment/Cluster/BlockGroup/Slices/TimeSlice/FrameNumber(Uint),
-//   #[id=0xCC] Segment/Cluster/BlockGroup/Slices/TimeSlice/LaceNumber(Uint),
-//   #[id=0xCF] Segment/Cluster/BlockGroup/Slices/TimeSlice/SliceDuration(Uint),
-//   #[id=0xAF] Segment/Cluster/EncryptedBlock(Vec<u8>),
-//   #[id=0xA7] Segment/Cluster/Position(Uint),
-//   #[id=0xAB] Segment/Cluster/PrevSize(Uint),
-//   #[id=0x5854] Segment/Cluster/SilentTracks(Master),
-//   #[id=0x58D7] Segment/Cluster/SilentTracks/SilentTrackNumber(Uint),
-//   #[id=0xA3] Segment/Cluster/SimpleBlock(Vec<u8>),
-//   #[id=0xE7] Segment/Cluster/Timestamp(Uint),
+    Segment[0x18538067]: {
+        Attachments[0x1941A469]: {
+            AttachedFile[0x61A7]: {
+                FileData[0x465C]: Binary,
+                FileDescription[0x467E]: Utf8,
+                FileMimeType[0x4660]: Utf8,
+                FileName[0x466E]: Utf8,
+                FileReferral[0x4675]: Binary,
+                FileUID[0x46AE]: Uint,
+                FileUsedEndTime[0x4662]: Uint,
+                FileUsedStartTime[0x4661]: Uint,
+            },
+        },
+        Chapters[0x1043A770]: {
+            EditionEntry[0x45B9]: {
+                ChapPterAtom[0xB6]: {
+                    ChapProcess[0x6944]: {
+                        ChapProcessCodecID[0x6955]: Uint,
+                        ChapProcessCommand[0x6911]: {
+                            ChapProcessData[0x6933]: Binary,
+                            ChapProcessTime[0x6922]: Uint,
+                        },
+                        ChapProcessPrivate[0x450D]: Binary,
+                    },
+                    ChapterDisplay[0x80]: {
+                        ChapCountry[0x437E]: Utf8,
+                        ChapLanguage[0x437C]: Utf8,
+                        ChapLanguageIETF[0x437D]: Utf8,
+                        ChapString[0x85]: Utf8,
+                    },
+                    ChapterFlagEnabled[0x4598]: Uint,
+                    ChapterFlagHidden[0x98]: Uint,
+                    ChapterPhysicalEquiv[0x63C3]: Uint,
+                    ChapterSegmentEditionUID[0x6EBC]: Uint,
+                    ChapterSegmentUID[0x6E67]: Binary,
+                    ChapterStringUID[0x5654]: Utf8,
+                    ChapterTimeEnd[0x92]: Uint,
+                    ChapterTimeStart[0x91]: Uint,
+                    ChapterUID[0x73C4]: Uint,
+                    ChapterTrack[0x8F]: {
+                        ChapterTrackUID[0x89]: Uint,
+                    },
+                },
+                EditionFlagDefault[0x45DB]: Uint,
+                EditionFlagHidden[0x45BD]: Uint,
+                EditionFlagOrdered[0x45DD]: Uint,
+                EditionUID[0x45BC]: Uint,
+            },
+        },
 
-//   #[id=0x1C53BB6B] Segment/Cues(Master),
-//   #[id=0xBB] Segment/Cues/CuePoint(Master),
-//   #[id=0xB3] Segment/Cues/CuePoint/CueTime(Uint),
-//   #[id=0xB7] Segment/Cues/CuePoint/CueTrackPositions(Master),
-//   #[id=0x5378] Segment/Cues/CuePoint/CueTrackPositions/CueBlockNumber(Uint),
-//   #[id=0xF1] Segment/Cues/CuePoint/CueTrackPositions/CueClusterPosition(Uint),
-//   #[id=0xEA] Segment/Cues/CuePoint/CueTrackPositions/CueCodecState(Uint),
-//   #[id=0xB2] Segment/Cues/CuePoint/CueTrackPositions/CueDuration(Uint),
-//   #[id=0xDB] Segment/Cues/CuePoint/CueTrackPositions/CueReference(Master),
-//   #[id=0x97] Segment/Cues/CuePoint/CueTrackPositions/CueReference/CueRefCluster(Uint),
-//   #[id=0xEB] Segment/Cues/CuePoint/CueTrackPositions/CueReference/CueRefCodecState(Uint),
-//   #[id=0x535F] Segment/Cues/CuePoint/CueTrackPositions/CueReference/CueRefNumber(Uint),
-//   #[id=0x96] Segment/Cues/CuePoint/CueTrackPositions/CueReference/CueRefTime(Uint),
-//   #[id=0xF0] Segment/Cues/CuePoint/CueTrackPositions/CueRelativePosition(Uint),
-//   #[id=0xF7] Segment/Cues/CuePoint/CueTrackPositions/CueTrack(Uint),
+        Cluster[0x1F43B675]: {
+            #[id=0xA0] BlockGroup: {
+                #[id=0xA1] Block(Binary),
+                #[id=0x75A1] BlockAdditions: {
+                    #[id=0xA6] BlockMore: {
+                        #[id=0xEE] BlockAddID(Uint),
+                        #[id=0xA5] BlockAdditional(Binary),
+                    },
+                },
+                #[id=0x9B] BlockDuration(Uint),
+                #[id=0xA2] BlockVirtual(Binary),
+                #[id=0xA4] CodecState(Binary),
+                #[id=0x75A2] DiscardPadding(Integer),
+                #[id=0xFB] ReferenceBlock(Integer),
+                #[id=0xC8] ReferenceFrame: {
+                    #[id=0xC9] ReferenceOffset(Uint),
+                    #[id=0xCA] ReferenceTimestamp(Uint),
+                },
+                #[id=0xFA] ReferencePriority(Uint),
+                #[id=0xFD] ReferenceVirtual(Integer),
+                #[id=0x8E] Slices: {
+                    #[id=0xE8] TimeSlice: {
+                        #[id=0xCB] BlockAdditionID(Uint),
+                        #[id=0xCE] Delay(Uint),
+                        #[id=0xCD] FrameNumber(Uint),
+                        #[id=0xCC] LaceNumber(Uint),
+                        #[id=0xCF] SliceDuration(Uint),
+                    },
+                },
+            },
+            #[id=0xAF] EncryptedBlock(Binary),
+            #[id=0xA7] Position(Uint),
+            #[id=0xAB] PrevSize(Uint),
+            #[id=0x5854] SilentTracks: {
+                #[id=0x58D7] SilentTrackNumber(Uint),
+            },
+            #[id=0xA3] SimpleBlock(Binary),
+            #[id=0xE7] Timestamp(Uint),
+        }
+    
+        #[id=0x1C53BB6B] Cues: {
+            #[id=0xBB] CuePoint: {
+                #[id=0xB3] CueTime(Uint),
+                #[id=0xB7] CueTrackPositions: {
+                    #[id=0x5378] CueBlockNumber(Uint),
+                    #[id=0xF1] CueClusterPosition(Uint),
+                    #[id=0xEA] CueCodecState(Uint),
+                    #[id=0xB2] CueDuration(Uint),
+                    #[id=0xDB] CueReference: {
+                        #[id=0x97] CueRefCluster(Uint),
+                        #[id=0xEB] CueRefCodecState(Uint),
+                        #[id=0x535F] CueRefNumber(Uint),
+                        #[id=0x96] CueRefTime(Uint),
+                    },
+                    #[id=0xF0] CueRelativePosition(Uint),
+                    #[id=0xF7] CueTrack(Uint),
+                },
+            },
+        },
 
-//   #[id=0x1549A966] Segment/Info(Master),
-//   #[id=0x6924] Segment/Info/ChapterTranslate(Master),
-//   #[id=0x69BF] Segment/Info/ChapterTranslate/ChapterTranslateCodec(Uint),
-//   #[id=0x69FC] Segment/Info/ChapterTranslate/ChapterTranslateEditionUID(Uint),
-//   #[id=0x69A5] Segment/Info/ChapterTranslate/ChapterTranslateID(Vec<u8>),
-//   #[id=0x4461] Segment/Info/DateUTC(Integer),
-//   #[id=0x4489] Segment/Info/Duration(Float),
-//   #[id=0x4D80] Segment/Info/MuxingApp(Utf8),
-//   #[id=0x3E83BB] Segment/Info/NextFilename(Utf8),
-//   #[id=0x3EB923] Segment/Info/NextUID(Vec<u8>),
-//   #[id=0x3C83AB] Segment/Info/PrevFilename(Utf8),
-//   #[id=0x3CB923] Segment/Info/PrevUID(Vec<u8>),
-//   #[id=0x4444] Segment/Info/SegmentFamily(Vec<u8>),
-//   #[id=0x7384] Segment/Info/SegmentFilename(Utf8),
-//   #[id=0x73A4] Segment/Info/SegmentUID(Vec<u8>),
-//   #[id=0x2AD7B1] Segment/Info/TimestampScale(Uint),
-//   #[id=0x7BA9] Segment/Info/Title(Utf8),
-//   #[id=0x5741] Segment/Info/WritingApp(Utf8),
+        #[id=0x1549A966] Info: {
+            #[id=0x6924] ChapterTranslate: {
+                #[id=0x69BF] ChapterTranslateCodec(Uint),
+                #[id=0x69FC] ChapterTranslateEditionUID(Uint),
+                #[id=0x69A5] ChapterTranslateID(Binary),
+            }
+            #[id=0x4461] DateUTC(Integer),
+            #[id=0x4489] Duration(Float),
+            #[id=0x4D80] MuxingApp(Utf8),
+            #[id=0x3E83BB] NextFilename(Utf8),
+            #[id=0x3EB923] NextUID(Binary),
+            #[id=0x3C83AB] PrevFilename(Utf8),
+            #[id=0x3CB923] PrevUID(Binary),
+            #[id=0x4444] SegmentFamily(Binary),
+            #[id=0x7384] SegmentFilename(Utf8),
+            #[id=0x73A4] SegmentUID(Binary),
+            #[id=0x2AD7B1] TimestampScale(Uint),
+            #[id=0x7BA9] Title(Utf8),
+            #[id=0x5741] WritingApp(Utf8),
+        },
 
-//   #[id=0x114D9B74] Segment/SeekHead(Master),
-//   #[id=0x4DBB] Segment/SeekHead/Seek(Master),
-//   #[id=0x53AB] Segment/SeekHead/Seek/SeekID(Vec<u8>),
-//   #[id=0x53AC] Segment/SeekHead/Seek/SeekPosition(Uint),
+        #[id=0x114D9B74] SeekHead: {
+            #[id=0x4DBB] Seek: {
+                #[id=0x53AB] SeekID(Binary),
+                #[id=0x53AC] SeekPosition(Uint),
+            },
+        },
 
-//   #[id=0x1254C367] Segment/Tags(Master),
-//   #[id=0x7373] Segment/Tags/Tag(Master),
-//   #[id=0x67C8] Segment/Tags/Tag/SimpleTag(Master),
-//   #[id=0x4485] Segment/Tags/Tag/SimpleTag/TagBinary(Vec<u8>),
-//   #[id=0x4484] Segment/Tags/Tag/SimpleTag/TagDefault(Uint),
-//   #[id=0x44B4] Segment/Tags/Tag/SimpleTag/TagDefaultBogus(Uint),
-//   #[id=0x447A] Segment/Tags/Tag/SimpleTag/TagLanguage(Utf8),
-//   #[id=0x447B] Segment/Tags/Tag/SimpleTag/TagLanguageIETF(Utf8),
-//   #[id=0x45A3] Segment/Tags/Tag/SimpleTag/TagName(Utf8),
-//   #[id=0x4487] Segment/Tags/Tag/SimpleTag/TagString(Utf8),
-//   #[id=0x63C0] Segment/Tags/Tag/Targets(Master),
-//   #[id=0x63C6] Segment/Tags/Tag/Targets/TagAttachmentUID(Uint),
-//   #[id=0x63C4] Segment/Tags/Tag/Targets/TagChapterUID(Uint),
-//   #[id=0x63C9] Segment/Tags/Tag/Targets/TagEditionUID(Uint),
-//   #[id=0x63C5] Segment/Tags/Tag/Targets/TagTrackUID(Uint),
-//   #[id=0x63CA] Segment/Tags/Tag/Targets/TargetType(Utf8),
-//   #[id=0x68CA] Segment/Tags/Tag/Targets/TargetTypeValue(Uint),
+        #[id=0x1254C367] Tags: {
+            #[id=0x7373] Tag: {
+                #[id=0x67C8] SimpleTag: {
+                    #[id=0x4485] TagBinary(Binary),
+                    #[id=0x4484] TagDefault(Uint),
+                    #[id=0x44B4] TagDefaultBogus(Uint),
+                    #[id=0x447A] TagLanguage(Utf8),
+                    #[id=0x447B] TagLanguageIETF(Utf8),
+                    #[id=0x45A3] TagName(Utf8),
+                    #[id=0x4487] TagString(Utf8),
+                },
+                #[id=0x63C0] Targets: {
+                    #[id=0x63C6] TagAttachmentUID(Uint),
+                    #[id=0x63C4] TagChapterUID(Uint),
+                    #[id=0x63C9] TagEditionUID(Uint),
+                    #[id=0x63C5] TagTrackUID(Uint),
+                    #[id=0x63CA] TargetType(Utf8),
+                    #[id=0x68CA] TargetTypeValue(Uint),
+                },
+            },
+        },
 
-//   #[id=0x1654AE6B] Segment/Tracks(Master),
-//   #[id=0xAE] Segment/Tracks/TrackEntry(Master),
-//   #[id=0x7446] Segment/Tracks/TrackEntry/AttachmentLink(Uint),
-//   #[id=0xE1] Segment/Tracks/TrackEntry/Audio(Master),
-//   #[id=0x6264] Segment/Tracks/TrackEntry/Audio/BitDepth(Uint),
-//   #[id=0x7D7B] Segment/Tracks/TrackEntry/Audio/ChannelPositions(Vec<u8>),
-//   #[id=0x9F] Segment/Tracks/TrackEntry/Audio/Channels(Uint),
-//   #[id=0x78B5] Segment/Tracks/TrackEntry/Audio/OutputSamplingFrequency(Float),
-//   #[id=0xB5] Segment/Tracks/TrackEntry/Audio/SamplingFrequency(Float),
-//   #[id=0x41E4] Segment/Tracks/TrackEntry/BlockAdditionMapping(Master),
-//   #[id=0x41ED] Segment/Tracks/TrackEntry/BlockAdditionMapping/BlockAddIDExtraData(Vec<u8>),
-//   #[id=0x41A4] Segment/Tracks/TrackEntry/BlockAdditionMapping/BlockAddIDName(Utf8),
-//   #[id=0x41E7] Segment/Tracks/TrackEntry/BlockAdditionMapping/BlockAddIDType(Uint),
-//   #[id=0x41F0] Segment/Tracks/TrackEntry/BlockAdditionMapping/BlockAddIDValue(Uint),
-//   #[id=0xAA] Segment/Tracks/TrackEntry/CodecDecodeAll(Uint),
-//   #[id=0x56AA] Segment/Tracks/TrackEntry/CodecDelay(Uint),
-//   #[id=0x26B240] Segment/Tracks/TrackEntry/CodecDownloadURL(Utf8),
-//   #[id=0x86] Segment/Tracks/TrackEntry/CodecID(Utf8),
-//   #[id=0x3B4040] Segment/Tracks/TrackEntry/CodecInfoURL(Utf8),
-//   #[id=0x258688] Segment/Tracks/TrackEntry/CodecName(Utf8),
-//   #[id=0x63A2] Segment/Tracks/TrackEntry/CodecPrivate(Vec<u8>),
-//   #[id=0x3A9697] Segment/Tracks/TrackEntry/CodecSettings(Utf8),
-//   #[id=0x6D80] Segment/Tracks/TrackEntry/ContentEncodings(Master),
-//   #[id=0x6240] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding(Master),
-//   #[id=0x5034] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentCompression(Master),
-//   #[id=0x4254] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentCompression/ContentCompAlgo(Uint),
-//   #[id=0x4255] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentCompression/ContentCompSettings(Vec<u8>),
-//   #[id=0x5031] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncodingOrder(Uint),
-//   #[id=0x5032] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncodingScope(Uint),
-//   #[id=0x5033] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncodingType(Uint),
-//   #[id=0x5035] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncryption(Master),
-//   #[id=0x47E7] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncryption/ContentEncAESSettings(Master),
-//   #[id=0x47E8] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncryption/ContentEncAESSettings/AESSettingsCipherMode(Uint),
-//   #[id=0x47E1] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncryption/ContentEncAlgo(Uint),
-//   #[id=0x47E2] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncryption/ContentEncKeyID(Vec<u8>),
-//   #[id=0x47E5] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncryption/ContentSigAlgo(Uint),
-//   #[id=0x47E6] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncryption/ContentSigHashAlgo(Uint),
-//   #[id=0x47E4] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncryption/ContentSigKeyID(Vec<u8>),
-//   #[id=0x47E3] Segment/Tracks/TrackEntry/ContentEncodings/ContentEncoding/ContentEncryption/ContentSignature(Vec<u8>),
-//   #[id=0x234E7A] Segment/Tracks/TrackEntry/DefaultDecodedFieldDuration(Uint),
-//   #[id=0x23E383] Segment/Tracks/TrackEntry/DefaultDuration(Uint),
-//   #[id=0x55AF] Segment/Tracks/TrackEntry/FlagCommentary(Uint),
-//   #[id=0x88] Segment/Tracks/TrackEntry/FlagDefault(Uint),
-//   #[id=0xB9] Segment/Tracks/TrackEntry/FlagEnabled(Uint),
-//   #[id=0x55AA] Segment/Tracks/TrackEntry/FlagForced(Uint),
-//   #[id=0x55AB] Segment/Tracks/TrackEntry/FlagHearingImpaired(Uint),
-//   #[id=0x9C] Segment/Tracks/TrackEntry/FlagLacing(Uint),
-//   #[id=0x55AE] Segment/Tracks/TrackEntry/FlagOriginal(Uint),
-//   #[id=0x55AD] Segment/Tracks/TrackEntry/FlagTextDescriptions(Uint),
-//   #[id=0x55AC] Segment/Tracks/TrackEntry/FlagVisualImpaired(Uint),
-//   #[id=0x22B59C] Segment/Tracks/TrackEntry/Language(Utf8),
-//   #[id=0x22B59D] Segment/Tracks/TrackEntry/LanguageIETF(Utf8),
-//   #[id=0x55EE] Segment/Tracks/TrackEntry/MaxBlockAdditionID(Uint),
-//   #[id=0x6DF8] Segment/Tracks/TrackEntry/MaxCache(Uint),
-//   #[id=0x6DE7] Segment/Tracks/TrackEntry/MinCache(Uint),
-//   #[id=0x536E] Segment/Tracks/TrackEntry/Name(Utf8),
-//   #[id=0x56BB] Segment/Tracks/TrackEntry/SeekPreRoll(Uint),
-//   #[id=0xD7] Segment/Tracks/TrackEntry/TrackNumber(Uint),
-//   #[id=0x537F] Segment/Tracks/TrackEntry/TrackOffset(Integer),
-//   #[id=0xE2] Segment/Tracks/TrackEntry/TrackOperation(Master),
-//   #[id=0xE3] Segment/Tracks/TrackEntry/TrackOperation/TrackCombinePlanes(Master),
-//   #[id=0xE4] Segment/Tracks/TrackEntry/TrackOperation/TrackCombinePlanes/TrackPlane(Master),
-//   #[id=0xE6] Segment/Tracks/TrackEntry/TrackOperation/TrackCombinePlanes/TrackPlane/TrackPlaneType(Uint),
-//   #[id=0xE5] Segment/Tracks/TrackEntry/TrackOperation/TrackCombinePlanes/TrackPlane/TrackPlaneUID(Uint),
-//   #[id=0xE9] Segment/Tracks/TrackEntry/TrackOperation/TrackJoinBlocks(Master),
-//   #[id=0xED] Segment/Tracks/TrackEntry/TrackOperation/TrackJoinBlocks/TrackJoinUID(Uint),
-//   #[id=0x6FAB] Segment/Tracks/TrackEntry/TrackOverlay(Uint),
-//   #[id=0x23314F] Segment/Tracks/TrackEntry/TrackTimestampScale(Float),
-//   #[id=0x6624] Segment/Tracks/TrackEntry/TrackTranslate(Master),
-//   #[id=0x66BF] Segment/Tracks/TrackEntry/TrackTranslate/TrackTranslateCodec(Uint),
-//   #[id=0x66FC] Segment/Tracks/TrackEntry/TrackTranslate/TrackTranslateEditionUID(Uint),
-//   #[id=0x66A5] Segment/Tracks/TrackEntry/TrackTranslate/TrackTranslateTrackID(Vec<u8>),
-//   #[id=0x83] Segment/Tracks/TrackEntry/TrackType(Uint),
-//   #[id=0x73C5] Segment/Tracks/TrackEntry/TrackUID(Uint),
-//   #[id=0xC4] Segment/Tracks/TrackEntry/TrickMasterTrackSegmentUID(Vec<u8>),
-//   #[id=0xC7] Segment/Tracks/TrackEntry/TrickMasterTrackUID(Uint),
-//   #[id=0xC6] Segment/Tracks/TrackEntry/TrickTrackFlag(Uint),
-//   #[id=0xC1] Segment/Tracks/TrackEntry/TrickTrackSegmentUID(Vec<u8>),
-//   #[id=0xC0] Segment/Tracks/TrackEntry/TrickTrackUID(Uint),
-//   #[id=0xE0] Segment/Tracks/TrackEntry/Video(Master),
-//   #[id=0x53C0] Segment/Tracks/TrackEntry/Video/AlphaMode(Uint),
-//   #[id=0x54B3] Segment/Tracks/TrackEntry/Video/AspectRatioType(Uint),
-//   #[id=0x55B0] Segment/Tracks/TrackEntry/Video/Colour(Master),
-//   #[id=0x55B2] Segment/Tracks/TrackEntry/Video/Colour/BitsPerChannel(Uint),
-//   #[id=0x55B5] Segment/Tracks/TrackEntry/Video/Colour/CbSubsamplingHorz(Uint),
-//   #[id=0x55B6] Segment/Tracks/TrackEntry/Video/Colour/CbSubsamplingVert(Uint),
-//   #[id=0x55B7] Segment/Tracks/TrackEntry/Video/Colour/ChromaSitingHorz(Uint),
-//   #[id=0x55B8] Segment/Tracks/TrackEntry/Video/Colour/ChromaSitingVert(Uint),
-//   #[id=0x55B3] Segment/Tracks/TrackEntry/Video/Colour/ChromaSubsamplingHorz(Uint),
-//   #[id=0x55B4] Segment/Tracks/TrackEntry/Video/Colour/ChromaSubsamplingVert(Uint),
-//   #[id=0x55D0] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata(Master),
-//   #[id=0x55D9] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata/LuminanceMax(Float),
-//   #[id=0x55DA] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata/LuminanceMin(Float),
-//   #[id=0x55D5] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata/PrimaryBChromaticityX(Float),
-//   #[id=0x55D6] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata/PrimaryBChromaticityY(Float),
-//   #[id=0x55D3] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata/PrimaryGChromaticityX(Float),
-//   #[id=0x55D4] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata/PrimaryGChromaticityY(Float),
-//   #[id=0x55D1] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata/PrimaryRChromaticityX(Float),
-//   #[id=0x55D2] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata/PrimaryRChromaticityY(Float),
-//   #[id=0x55D7] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata/WhitePointChromaticityX(Float),
-//   #[id=0x55D8] Segment/Tracks/TrackEntry/Video/Colour/MasteringMetadata/WhitePointChromaticityY(Float),
-//   #[id=0x55B1] Segment/Tracks/TrackEntry/Video/Colour/MatrixCoefficients(Uint),
-//   #[id=0x55BC] Segment/Tracks/TrackEntry/Video/Colour/MaxCLL(Uint),
-//   #[id=0x55BD] Segment/Tracks/TrackEntry/Video/Colour/MaxFALL(Uint),
-//   #[id=0x55BB] Segment/Tracks/TrackEntry/Video/Colour/Primaries(Uint),
-//   #[id=0x55B9] Segment/Tracks/TrackEntry/Video/Colour/Range(Uint),
-//   #[id=0x55BA] Segment/Tracks/TrackEntry/Video/Colour/TransferCharacteristics(Uint),
-//   #[id=0x54BA] Segment/Tracks/TrackEntry/Video/DisplayHeight(Uint),
-//   #[id=0x54B2] Segment/Tracks/TrackEntry/Video/DisplayUnit(Uint),
-//   #[id=0x54B0] Segment/Tracks/TrackEntry/Video/DisplayWidth(Uint),
-//   #[id=0x9D] Segment/Tracks/TrackEntry/Video/FieldOrder(Uint),
-//   #[id=0x9A] Segment/Tracks/TrackEntry/Video/FlagInterlaced(Uint),
-//   #[id=0x2383E3] Segment/Tracks/TrackEntry/Video/FrameRate(Float),
-//   #[id=0x2FB523] Segment/Tracks/TrackEntry/Video/GammaValue(Float),
-//   #[id=0x53B9] Segment/Tracks/TrackEntry/Video/OldStereoMode(Uint),
-//   #[id=0x54AA] Segment/Tracks/TrackEntry/Video/PixelCropBottom(Uint),
-//   #[id=0x54CC] Segment/Tracks/TrackEntry/Video/PixelCropLeft(Uint),
-//   #[id=0x54DD] Segment/Tracks/TrackEntry/Video/PixelCropRight(Uint),
-//   #[id=0x54BB] Segment/Tracks/TrackEntry/Video/PixelCropTop(Uint),
-//   #[id=0xBA] Segment/Tracks/TrackEntry/Video/PixelHeight(Uint),
-//   #[id=0xB0] Segment/Tracks/TrackEntry/Video/PixelWidth(Uint),
-//   #[id=0x7670] Segment/Tracks/TrackEntry/Video/Projection(Master),
-//   #[id=0x7674] Segment/Tracks/TrackEntry/Video/Projection/ProjectionPosePitch(Float),
-//   #[id=0x7675] Segment/Tracks/TrackEntry/Video/Projection/ProjectionPoseRoll(Float),
-//   #[id=0x7673] Segment/Tracks/TrackEntry/Video/Projection/ProjectionPoseYaw(Float),
-//   #[id=0x7672] Segment/Tracks/TrackEntry/Video/Projection/ProjectionPrivate(Vec<u8>),
-//   #[id=0x7671] Segment/Tracks/TrackEntry/Video/Projection/ProjectionType(Uint),
-//   #[id=0x53B8] Segment/Tracks/TrackEntry/Video/StereoMode(Uint),
-//   #[id=0x2EB524] Segment/Tracks/TrackEntry/Video/UncompressedFourCC(Vec<u8>)
+        #[id=0x1654AE6B] Tracks: {
+            #[id=0xAE] TrackEntry: {
+                #[id=0x7446] AttachmentLink(Uint),
+                #[id=0xE1] Audio: {
+                    #[id=0x6264] BitDepth(Uint),
+                    #[id=0x7D7B] ChannelPositions(Binary),
+                    #[id=0x9F] Channels(Uint),
+                    #[id=0x78B5] OutputSamplingFrequency(Float),
+                    #[id=0xB5] SamplingFrequency(Float),
+                }
+                #[id=0x41E4] BlockAdditionMapping: {
+                    #[id=0x41ED] BlockAddIDExtraData(Binary),
+                    #[id=0x41A4] BlockAddIDName(Utf8),
+                    #[id=0x41E7] BlockAddIDType(Uint),
+                    #[id=0x41F0] BlockAddIDValue(Uint),
+                }
+                #[id=0xAA] CodecDecodeAll(Uint),
+                #[id=0x56AA] CodecDelay(Uint),
+                #[id=0x26B240] CodecDownloadURL(Utf8),
+                #[id=0x86] CodecID(Utf8),
+                #[id=0x3B4040] CodecInfoURL(Utf8),
+                #[id=0x258688] CodecName(Utf8),
+                #[id=0x63A2] CodecPrivate(Binary),
+                #[id=0x3A9697] CodecSettings(Utf8),
+                #[id=0x6D80] ContentEncodings: {
+                    #[id=0x6240] ContentEncoding: {
+                        #[id=0x5034] ContentCompression: {
+                            #[id=0x4254] ContentCompAlgo(Uint),
+                            #[id=0x4255] ContentCompSettings(Binary),
+                        },
+                        #[id=0x5031] ContentEncodingOrder(Uint),
+                        #[id=0x5032] ContentEncodingScope(Uint),
+                        #[id=0x5033] ContentEncodingType(Uint),
+                        #[id=0x5035] ContentEncryption: {
+                            #[id=0x47E7] ContentEncAESSettings: {
+                                #[id=0x47E8] AESSettingsCipherMode(Uint),
+                            }
+                            #[id=0x47E1] ContentEncAlgo(Uint),
+                            #[id=0x47E2] ContentEncKeyID(Binary),
+                            #[id=0x47E5] ContentSigAlgo(Uint),
+                            #[id=0x47E6] ContentSigHashAlgo(Uint),
+                            #[id=0x47E4] ContentSigKeyID(Binary),
+                            #[id=0x47E3] ContentSignature(Binary),
+                        },
+                    },
+                },
+                #[id=0x234E7A] DefaultDecodedFieldDuration(Uint),
+                #[id=0x23E383] DefaultDuration(Uint),
+                #[id=0x55AF] FlagCommentary(Uint),
+                #[id=0x88] FlagDefault(Uint),
+                #[id=0xB9] FlagEnabled(Uint),
+                #[id=0x55AA] FlagForced(Uint),
+                #[id=0x55AB] FlagHearingImpaired(Uint),
+                #[id=0x9C] FlagLacing(Uint),
+                #[id=0x55AE] FlagOriginal(Uint),
+                #[id=0x55AD] FlagTextDescriptions(Uint),
+                #[id=0x55AC] FlagVisualImpaired(Uint),
+                #[id=0x22B59C] Language(Utf8),
+                #[id=0x22B59D] LanguageIETF(Utf8),
+                #[id=0x55EE] MaxBlockAdditionID(Uint),
+                #[id=0x6DF8] MaxCache(Uint),
+                #[id=0x6DE7] MinCache(Uint),
+                #[id=0x536E] Name(Utf8),
+                #[id=0x56BB] SeekPreRoll(Uint),
+                #[id=0xD7] TrackNumber(Uint),
+                #[id=0x537F] TrackOffset(Integer),
+                #[id=0xE2] TrackOperation: {
+                    #[id=0xE3] TrackCombinePlanes: {
+                        #[id=0xE4] TrackPlane: {
+                            #[id=0xE6] TrackPlaneType(Uint),
+                            #[id=0xE5] TrackPlaneUID(Uint),
+                        },
+                    },
+                    #[id=0xE9] TrackJoinBlocks: {
+                        #[id=0xED] TrackJoinUID(Uint),
+                    },
+                }
+                #[id=0x6FAB] TrackOverlay(Uint),
+                #[id=0x23314F] TrackTimestampScale(Float),
+                #[id=0x6624] TrackTranslate: {
+                    #[id=0x66BF] TrackTranslateCodec(Uint),
+                    #[id=0x66FC] TrackTranslateEditionUID(Uint),
+                    #[id=0x66A5] TrackTranslateTrackID(Binary),
+                },
+                #[id=0x83] TrackType(Uint),
+                #[id=0x73C5] TrackUID(Uint),
+                #[id=0xC4] TrickMasterTrackSegmentUID(Binary),
+                #[id=0xC7] TrickMasterTrackUID(Uint),
+                #[id=0xC6] TrickTrackFlag(Uint),
+                #[id=0xC1] TrickTrackSegmentUID(Binary),
+                #[id=0xC0] TrickTrackUID(Uint),
+                #[id=0xE0] Video: {
+                    #[id=0x53C0] AlphaMode(Uint),
+                    #[id=0x54B3] AspectRatioType(Uint),
+                    #[id=0x55B0] Colour: {
+                        #[id=0x55B2] BitsPerChannel(Uint),
+                        #[id=0x55B5] CbSubsamplingHorz(Uint),
+                        #[id=0x55B6] CbSubsamplingVert(Uint),
+                        #[id=0x55B7] ChromaSitingHorz(Uint),
+                        #[id=0x55B8] ChromaSitingVert(Uint),
+                        #[id=0x55B3] ChromaSubsamplingHorz(Uint),
+                        #[id=0x55B4] ChromaSubsamplingVert(Uint),
+                        #[id=0x55D0] MasteringMetadata: {
+                            #[id=0x55D9] LuminanceMax(Float),
+                            #[id=0x55DA] LuminanceMin(Float),
+                            #[id=0x55D5] PrimaryBChromaticityX(Float),
+                            #[id=0x55D6] PrimaryBChromaticityY(Float),
+                            #[id=0x55D3] PrimaryGChromaticityX(Float),
+                            #[id=0x55D4] PrimaryGChromaticityY(Float),
+                            #[id=0x55D1] PrimaryRChromaticityX(Float),
+                            #[id=0x55D2] PrimaryRChromaticityY(Float),
+                            #[id=0x55D7] WhitePointChromaticityX(Float),
+                            #[id=0x55D8] WhitePointChromaticityY(Float),
+                        },
+                        #[id=0x55B1] MatrixCoefficients(Uint),
+                        #[id=0x55BC] MaxCLL(Uint),
+                        #[id=0x55BD] MaxFALL(Uint),
+                        #[id=0x55BB] Primaries(Uint),
+                        #[id=0x55B9] Range(Uint),
+                        #[id=0x55BA] TransferCharacteristics(Uint),
+                    },
+                    #[id=0x54BA] DisplayHeight(Uint),
+                    #[id=0x54B2] DisplayUnit(Uint),
+                    #[id=0x54B0] DisplayWidth(Uint),
+                    #[id=0x9D] FieldOrder(Uint),
+                    #[id=0x9A] FlagInterlaced(Uint),
+                    #[id=0x2383E3] FrameRate(Float),
+                    #[id=0x2FB523] GammaValue(Float),
+                    #[id=0x53B9] OldStereoMode(Uint),
+                    #[id=0x54AA] PixelCropBottom(Uint),
+                    #[id=0x54CC] PixelCropLeft(Uint),
+                    #[id=0x54DD] PixelCropRight(Uint),
+                    #[id=0x54BB] PixelCropTop(Uint),
+                    #[id=0xBA] PixelHeight(Uint),
+                    #[id=0xB0] PixelWidth(Uint),
+                    #[id=0x7670] Projection: {
+                        #[id=0x7674] ProjectionPosePitch(Float),
+                        #[id=0x7675] ProjectionPoseRoll(Float),
+                        #[id=0x7673] ProjectionPoseYaw(Float),
+                        #[id=0x7672] ProjectionPrivate(Binary),
+                        #[id=0x7671] ProjectionType(Uint),
+                    },
+                    #[id=0x53B8] StereoMode(Uint),
+                    #[id=0x2EB524] UncompressedFourCC(Binary),
+                },
+            },
+        },
+    },
+}
\ No newline at end of file
diff --git a/ebml/src/read.rs b/ebml/src/read.rs
index 7431683..23b4e21 100644
--- a/ebml/src/read.rs
+++ b/ebml/src/read.rs
@@ -1,5 +1,7 @@
+use anyhow::{bail, Result};
 use std::io::{Read, Seek};
-use anyhow::Result;
+
+use crate::matroska::MatroskaTag;
 
 trait ReadAndSeek: Read + Seek {}
 impl<T: Read + Seek> ReadAndSeek for T {}
@@ -37,9 +39,12 @@ impl EbmlReader {
     pub fn read_vint_len(&mut self) -> Result<(u64, usize)> {
         let s = self.read_byte()?;
         let len = s.leading_zeros() + 1;
+        if len > 8 {
+            bail!("varint too long");
+        }
         let mut value = s as u64;
         value -= 1 << (8 - len);
-        for _ in 0..(len - 1) {
+        for _ in 1..len {
             value <<= 8;
             value += self.read_byte()? as u64;
         }
@@ -52,11 +57,23 @@ impl EbmlReader {
         let b = self.read_buf(size)?;
         Ok(String::from_utf8(b)?)
     }
-
     pub fn read_tag_id(&mut self) -> Result<u64> {
         let (value, len) = self.read_vint_len()?;
         Ok(value + (1 << (7 * len)))
     }
+    pub fn read_tag_size(&mut self) -> Result<EbmlSize> {
+        Ok(EbmlSize::from_vint(self.read_vint_len()?))
+    }
+    pub fn read_tag(&mut self) -> Result<MatroskaTag> {
+        let id = self.read_tag_id()?;
+        let size = self.read_tag_size()?;
+        if MatroskaTag::is_master(id)? {
+            Ok(MatroskaTag::parse(id, &[])?)
+        } else {
+            let data = self.read_buf(size)?;
+            Ok(MatroskaTag::parse(id, &data)?)
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -65,20 +82,12 @@ pub enum EbmlSize {
     Unknown,
 }
 impl EbmlSize {
-    #[rustfmt::skip]
     pub fn from_vint((value, len): (u64, usize)) -> EbmlSize {
-        match len {
-            1 => if value == ((1 << (7))     - 1) { return Self::Unknown; },
-            2 => if value == ((1 << (7 * 2)) - 1) { return Self::Unknown; },
-            3 => if value == ((1 << (7 * 3)) - 1) { return Self::Unknown; },
-            4 => if value == ((1 << (7 * 4)) - 1) { return Self::Unknown; },
-            5 => if value == ((1 << (7 * 5)) - 1) { return Self::Unknown; },
-            6 => if value == ((1 << (7 * 6)) - 1) { return Self::Unknown; },
-            7 => if value == ((1 << (7 * 7)) - 1) { return Self::Unknown; },
-            8 => if value == ((1 << (7 * 8)) - 1) { return Self::Unknown; },
-            _ => {},
+        if value == ((1 << (7 * len)) - 1) {
+            Self::Unknown
+        } else {
+            Self::Exact(value as usize)
         }
-        Self::Exact(len)
     }
 }
 impl Into<usize> for EbmlSize {