Media Recording - MediaRecorder's mimeType attribute maybe null after call the start()

RESOLVED INVALID

Status

()

RESOLVED INVALID
5 years ago
5 years ago

People

(Reporter: rlin, Assigned: rlin)

Tracking

25 Branch
x86_64
Windows 7
Points:
---

Firefox Tracking Flags

(Not tracked)

Details

We set the mimeType when encoder return the first data, so there is a timing issue to cause this value to be null.

Updated

5 years ago
Blocks: 896935
Assignee: nobody → rlin
Hi Roc,
Should we make mimeType decision in 
MediaRecorder:start() function by...
1. User set mimeType preference (not done yet) 
2. check the mediaStream has 
  1. only has video track ->imply record the video/webm or ??
  2. only has audio track ->imply record the audio/ogg
  3. both->imply record the video/webm or ??

Or let the encoder choose the suitable mimetpye form mediaStream?
Flags: needinfo?(roc)
We need to let the encoder choose the MIME type based on the MediaStream, and we can't do that synchronously in start().
Flags: needinfo?(roc)
I set this issue to be invalid due to the mimeType would be provided when the encoder start to pass out the encoded data.
Status: NEW → RESOLVED
Last Resolved: 5 years ago
Resolution: --- → INVALID
(In reply to Randy Lin [:rlin] from comment #3)
> I set this issue to be invalid due to the mimeType would be provided when
> the encoder start to pass out the encoded data.

But how would a web developer know that? Shouldn't we have an onXXX handler to give a web developer knowledge that the mime type has been populated and be ready for use?
Flags: needinfo?(roc)
Looking at the spec, the only event handler that might be a potential candidate here to use would be the onstart event handler. Do we need to implement support for that event handler here to allow a web developer to know the mime type is ready for use?
I think probably the MIME type should only be available when the first Blob is delivered.
Flags: needinfo?(roc)

Updated

5 years ago
No longer blocks: 889772, 896935
Component: Video/Audio → Video/Audio: Recording
You need to log in before you can comment on or make changes to this bug.