diff --git a/src/util/mod.rs b/src/util/mod.rs
index e69de29..9a8d351 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -0,0 +1,53 @@
+use std::error::Error;
+use std::fmt;
+
+pub struct VideoMetadata {
+    pub width: u32,
+    pub height: u32,
+    pub framerate: f32,
+    pub codec: Option<VideoCodec>,
+}
+
+pub enum VideoCodec {
+    H264,
+}
+
+pub struct AudioMetadata {
+    pub samplerate: u32,
+    pub channels: u8,
+    pub codec: Option<AudioCodec>,
+}
+
+pub enum AudioCodec {
+    AAC,
+}
+
+pub struct Metadata {
+    pub video: VideoMetadata,
+    pub audio: AudioMetadata,
+}
+
+pub enum FileType {
+    FLV,
+    MPEGTS,
+}
+
+pub enum NALUPacketType {
+    Audio,
+    Video,
+}
+
+pub struct NALUPacket {
+    pub packet_type: NALUPacketType,
+    pub packet_data: Vec<u8>,
+}
+
+pub enum RawMediaType {
+    YUV420P,
+    PCM16LE,
+}
+
+pub struct RawMedia {
+    pub media_type: RawMediaType,
+    pub sample: Vec<u8>,
+}