fix: assign encoder timebase from sample rate

src/audio_fifo.rs

@@ -81,7 +81,7 @@ mod tests {
 
             let mut enc = Encoder::new_with_name("libfdk_aac")?
                 .with_sample_format(AVSampleFormat::AV_SAMPLE_FMT_S16)
-                .with_sample_rate(48_000)
+                .with_sample_rate(48_000)?
                 .with_default_channel_layout(2)
                 .open(None)?;
 

src/encode.rs

@@ -108,9 +108,13 @@ impl Encoder {
     }
 
     /// Set the encoder sample rate (audio)
-    pub unsafe fn with_sample_rate(self, fmt: i32) -> Self {
-        (*self.ctx).sample_rate = fmt;
-        self
+    pub unsafe fn with_sample_rate(self, rate: i32) -> Result<Self> {
+        if (*self.ctx).time_base.num != 1 || (*self.ctx).time_base.den != 1 {
+            bail!("Cannot assign sample_rate for a video encoder")
+        }
+        (*self.ctx).sample_rate = rate;
+        (*self.ctx).time_base = AVRational { num: 1, den: rate };
+        Ok(self)
     }
 
     /// Set the encoder width in pixels
@@ -138,11 +142,14 @@ impl Encoder {
     }
 
     /// Set the encoder framerate
-    pub unsafe fn with_framerate(self, fps: f32) -> Self {
+    pub unsafe fn with_framerate(self, fps: f32) -> Result<Self> {
+        if (*self.ctx).time_base.num != 1 || (*self.ctx).time_base.den != 1 {
+            bail!("Cannot assign framerate for an audio encoder")
+        }
         let q = av_d2q(fps as f64, 90_000);
         (*self.ctx).framerate = q;
         (*self.ctx).time_base = av_inv_q(q);
-        self
+        Ok(self)
     }
 
     /// Set the encoder pixel format

src/mux.rs

@@ -400,7 +400,7 @@ mod tests {
             .with_height((*frame).height)
             .with_pix_fmt(AV_PIX_FMT_YUV420P)
             .with_bitrate(1_000_000)
-            .with_framerate(30.0)
+            .with_framerate(30.0)?
             .with_profile(AV_PROFILE_H264_MAIN)
             .with_level(50)
             .open(None)?;