Bugzilla

The second track contains an `fmra` (OriginalFormatBox) box with the following 4 bytes values: 109, 112, 180, 97. This does not represent a valid UTF-8 string, so versions of `mp4parse-rust` prior to [761cdd8](https://github.com/mozilla/mp4parse-rust/commit/761cdd8082f198abe9434935846d6cd4475c5512) would fail to parse the file since the `read_frma` function returned a `Result<String>`. Subsequent versions (which have not yet been added to mozilla-central) change the return type to `Result<TryString>` (an alias for `TryVec<u8>`, a vector which uses fallible allocation), and so parsing succeeds.

According to ISO/IEC 14496-12:2015, the `frma` box's contents are not guaranteed to be UTF-8, so this file should successfully parse:

**8.12.2.2 Syntax**
```
aligned(8) class OriginalFormatBox(codingname) extends Box ('frma') {
   unsigned int(32)  data_format = codingname;
                     // format of decrypted, encoded data (in case of protection)
                     // or un-transformed sample entry (in case of restriction
                     // and complete track information)
}
```
**8.12.2.3 Semantics**

`data_format` is the four‐character‐code of the original un‐transformed sample entry (e.g. ‘mp4v’ if the stream contains protected or restricted MPEG‐4 visual material).

The second track contains an `fmra` (OriginalFormatBox) box with the following 4 bytes values: 109, 112, 180, 97. This does not represent a valid UTF-8 string, so versions of `mp4parse-rust` prior to [761cdd8](https://github.com/mozilla/mp4parse-rust/commit/761cdd8082f198abe9434935846d6cd4475c5512) would fail to parse the file since the `read_frma` function [returned a `Result<String>`](https://github.com/mozilla/mp4parse-rust/blob/921314e7baa8a26710269de53251a22b1cf3943d/mp4parse/src/lib.rs#L3531). Subsequent versions (which have not yet been added to mozilla-central) [change the return type to `Result<TryString>`](https://github.com/mozilla/mp4parse-rust/blob/761cdd8082f198abe9434935846d6cd4475c5512/mp4parse/src/lib.rs#L3654) (an alias for `TryVec<u8>`, a vector which uses fallible allocation), and so parsing succeeds.

According to ISO/IEC 14496-12:2015, the `frma` box's contents are not guaranteed to be UTF-8, so this file should successfully parse:

**8.12.2.2 Syntax**
```
aligned(8) class OriginalFormatBox(codingname) extends Box ('frma') {
   unsigned int(32)  data_format = codingname;
                     // format of decrypted, encoded data (in case of protection)
                     // or un-transformed sample entry (in case of restriction
                     // and complete track information)
}
```
**8.12.2.3 Semantics**

`data_format` is the four‐character‐code of the original un‐transformed sample entry (e.g. ‘mp4v’ if the stream contains protected or restricted MPEG‐4 visual material).