[mythtv-users] Repairing corrupt recordings with dd

[John Pilkington]

On 23/06/2020 15:21, DaveD wrote:
> A while back (few weeks?) someone posted info about a technique to strip 
> the first few megabytes from the beginning of a recording using dd.  It 
> involved a discussion about the new video rendering system crashing the 
> frontend (or casing decoder errors) on recordings where the format 
> changes soon after the recording starts.  I swear I saved that message 
> somewhere because I have a lot of those (thanks to Comcast and my 
> firewire recordings) but I'll be dipped if I can find it.  I've searched 
> the archives, too, with no luck.  I could probably figure it our from 
> the dd man page, but thought I'd ask for a re-post of that info since 
> it's a tried and tested method.  Thanks,
> 
> Dave D.
> 
I think you might be remembering this:

https://code.mythtv.org/trac/ticket/13557#comment:13

which looked for an appropriate skip value. applied it, and then rebuilt 
the seektable.  The output file doesn't start at a keyframe, but that 
doesn't seem to matter.

John P