isomp4: set mdhd.duration with adjusted timescale, reverts PR #317

symphonia-format-isomp4/src/atoms/moov.rs

@@ -69,9 +69,10 @@ impl Atom for MoovAtom {
             }
         }
 
-        if mvhd.is_none() {
+        let Some(mvhd) = mvhd
+        else {
             return decode_error("isomp4: missing mvhd atom");
-        }
+        };
 
         // If fragmented, the mvex atom should contain a trex atom for each trak atom in moov.
         if let Some(mvex) = mvex.as_ref() {
@@ -85,6 +86,14 @@ impl Atom for MoovAtom {
             }
         }
 
-        Ok(MoovAtom { mvhd: mvhd.unwrap(), traks, mvex, udta })
+        // If trak.mdia.mdhd.duration is 0, set it to trak.tkhd.duration converted to trak.mdia.mdhd.timescale
+        for trak in traks.iter_mut() {
+            if trak.mdia.mdhd.duration == 0 {
+                trak.mdia.mdhd.duration =
+                    trak.tkhd.duration * trak.mdia.mdhd.timescale as u64 / mvhd.timescale as u64;
+            }
+        }
+
+        Ok(MoovAtom { mvhd, traks, mvex, udta })
     }
 }

symphonia-format-isomp4/src/atoms/trak.rs

@@ -20,8 +20,6 @@ pub struct TrakAtom {
     pub edts: Option<EdtsAtom>,
     /// Media atom.
     pub mdia: MdiaAtom,
-    /// Duration, equal to mdia.mdhd.duration unless it is zero, in which case it is equal to tkhd.duration.
-    pub duration: u64,
 }
 
 impl Atom for TrakAtom {
@@ -47,19 +45,16 @@ impl Atom for TrakAtom {
             }
         }
 
-        let Some(tkhd_atom) = tkhd
+        let Some(tkhd) = tkhd
         else {
             return decode_error("isomp4: missing tkhd atom");
         };
 
-        let Some(mdia_atom) = mdia
+        let Some(mdia) = mdia
         else {
             return decode_error("isomp4: missing mdia atom");
         };
 
-        let duration =
-            if mdia_atom.mdhd.duration != 0 { mdia_atom.mdhd.duration } else { tkhd_atom.duration };
-
-        Ok(TrakAtom { tkhd: tkhd_atom, edts, mdia: mdia_atom, duration })
+        Ok(TrakAtom { tkhd, edts, mdia })
     }
 }

symphonia-format-isomp4/src/demuxer.rs

@@ -56,7 +56,7 @@ impl TrackState {
 
         track
             .with_time_base(TimeBase::new(1, trak.mdia.mdhd.timescale))
-            .with_num_frames(trak.duration);
+            .with_num_frames(trak.mdia.mdhd.duration);
 
         let state = Self {
             track_num,

symphonia-format-isomp4/src/stream.rs

@@ -146,7 +146,7 @@ impl StreamSegment for MoofSegment {
             }
 
             // If a track does NOT end in this segment, then this cannot be the last segment.
-            if seq.first_ts + seq.total_sample_duration < trak.duration {
+            if seq.first_ts + seq.total_sample_duration < trak.mdia.mdhd.duration {
                 return false;
             }
         }
@@ -349,7 +349,7 @@ impl StreamSegment for MoovSegment {
     fn all_tracks_ended(&self) -> bool {
         // If a track does not end in this segment, then this cannot be the last segment.
         for trak in &self.moov.traks {
-            if trak.mdia.minf.stbl.stts.total_duration < trak.duration {
+            if trak.mdia.minf.stbl.stts.total_duration < trak.mdia.mdhd.duration {
                 return false;
             }
         }