Ticket #10658 (accepted Developer Task)
Opened 13 months ago
Last modified 10 months ago
Allow partial AVFRingBuffer reads
| Reported by: | danielk | Owned by: | danielk |
|---|---|---|---|
| Priority: | minor | Milestone: | 0.27 |
| Component: | MythTV - General | Version: | Master Head |
| Severity: | medium | Keywords: | |
| Cc: | Ticket locked: | no |
Description (last modified by danielk) (diff)
Traditionally we've always had RingBuffer::Read() return the number of bytes requested unless we are at the end of the file. But this blocks libav which expects this the read to complete fairly quickly even if it is a blocking read. Instead we should block for only a short time waiting for more data and then return what data we do have as long as we have at least 1 byte of data.
Attachments
Change History
Changed 13 months ago by danielk
- Attachment 10658-v1.patch added
comment:1 Changed 13 months ago by danielk
- Owner set to danielk
- Status changed from new to accepted
- Version changed from Unspecified to Master Head
- Type changed from Bug Report - General to Developer Task
comment:3 Changed 10 months ago by danielk
With some debugging I've discovered that if you return -EAGAIN a number of times to libav it will mark the stream as having hit EOF. Even if you later reset the EOF flag any partially decoded data will be chucked by libav.
This means this solution is unworkable as is. However, we can still return partial reads as long as we avoid returning zero byte reads or -EAGAIN reads.
Changed 10 months ago by danielk
- Attachment 10658-v2.patch added
Rework which allows short reads, but still avoids ever returning 0 bytes.
comment:4 Changed 10 months ago by danielk
- Description modified (diff)
- Summary changed from Rework AVFRingBuffer to return -EAGAIN when there is no data to Allow partial AVFRingBuffer reads
Changed 10 months ago by anonymous
- Attachment 10490-debug-start-new-rec-every-30-sec-v2.patch added
debugging patch
Initial patch