Opened 14 years ago
Closed 14 years ago
#9577 closed Patch - Bug Fix (fixed)
CEA-708 captions sometimes spontaneously reset
| Reported by: | Owned by: | danielk | |
|---|---|---|---|
| Priority: | minor | Milestone: | 0.25 |
| Component: | MythTV - ATSC | Version: | 0.24-fixes |
| Severity: | medium | Keywords: | cea-708 |
| Cc: | Ticket locked: | no |
Description
Sometimes the CEA-708 closed caption decoder resets the caption display spontaneously, making the captions unreadable. Upon investigation, I found that the code which detects reset (RST) and delay cancel (DLC) commands in the parse_cc_service_stream function is incorrect. It should only inspect command bytes, but it actually scans parameter bytes as well. These parameter bytes may coincide with RST and DLC, causing an undesired reset in the former case, or a premature delay cancel in the latter.
To solve this problem, I added code to skip over parameter bytes. The list of commands and their corresponding number of parameter bytes were taken from the CEA-708 specification. I tested the code on a number of shows, and it now correctly skips over parameter bytes (verified with printf debugging), and the spontaneous resets are gone.
Attachments (1)
Change History (4)
Changed 14 years ago by
| Attachment: | caption-rst-dlc-fix.patch added |
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comment:1 Changed 14 years ago by
comment:2 Changed 14 years ago by
| Type: | Bug Report → Patch - Bug Fix |
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comment:3 Changed 14 years ago by
| Milestone: | unknown → 0.25 |
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| Resolution: | → fixed |
| Status: | new → closed |
CEA-708: Fix spontaneous resets. Closes #9577
Signed-off-by: Mark Kendall <mkendall@…>
Changeset: eebd67a1db7d6f30334b4aba908f6d9ee859882b
Oops, I meant to set the type to "Patch - Bug Fix".