File position seek support for MythTV recordings in progress
#1
There doesn't appear to be support for seeking within files that are currently being recorded by Myth TV. This appears to be intentional as described in Rewind not working as unable to seek in a file being recorded by MythTV.

A lack of this functionality means that Live TV isn't as useful as it could be in the existing myth:// protocol support added by elupus.

One of the XBMC GSoC projects that alcoheca is working on is to provide One unified PVR/DVR/HTPC front-end (client GUI) that would likely also need XBMC to support seeking for Live TV from the recording current in progress in the PVR backend Huh

I'm going to be upgrading to a Linux HTPC soon to watch digital terrestrial H264 720p broadcasts. This will (hopefully) all be done through XBMC and the current myth:// support until the GSoC project is further along. Not being able to rewind or skip backwards while watching Live TV will significantly decrease the WAF.

What are the options for getting support for file seeking within Myth TV recordings in progress Huh
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#2
According to the MythTV entry at Wikipedia:

Quote:The default file format for software encoding is a RTJPEG or MPEG-4 video stored in a slightly-modified version of Roman Hochleitner's NuppelVideo (.nuv) container. NUV files are also playable in VLC media player and MPlayer, but can occasionally exhibit problems in A/V synchronization due to the MythTV-specific modifications. It also appears that MythTV is now the single authority on the NuppelVideo file format, since the original author's website now appears to have been deleted.

MythTV can also record via hardware-encoder cards and other sources of MPEG-2 digital TV streams like DVB, ATSC and Firewire (from HDTV cable boxes in the United States), so many users of MythTV rarely see NuppelVideo files unless they choose to transcode their files to NuppelVideo to save disk space. In earlier releases, such files were labeled as .nuv, even though they were raw MPEG streams; this has been corrected in recent releases.

I've just checked and all of my recordings on disk are .mpg files (likely MPEG-2 as I'm using an MPEG-2 hardware decoder from the existing analog TV source).

Seeking within recordings that have finished recording is working fine, so I'm not sure what would cause it to not work for recordings still in progress...

Maybe it's something to do with the way the myth:// protocol opens the file?

Debug log located at http://pastebin.com/m51f0766f. Loads of the following in the file:

Code:
15:32:48 M: 26140672 WARNING: error while seeking
15:32:48 M: 26148864   DEBUG: CDVDPlayer::Process - Seeking to catch up
15:32:48 M: 26148864   DEBUG: demuxer seek to: 1945203
15:32:48 M: 26148864   DEBUG: XFILE::CCMythFile::Seek - seek to pos 0, whence 16
15:32:48 M: 26148864   DEBUG: CDVDDemuxFFmpeg::SeekTime - input stream reports it is not seekable
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#3
hi dteirney,

yeah I've noticed this too - it actually killed some recordings I was making at the time, not good for household relations.

there's no reason why mythtv can't read from a file it's writing to at the same time, it may be trying to set up two concurrent recordings, not sure. It could also be something to do with the xbmc session handling or libcmyth.

Now I don't use myth:// for anything but watching recordings that have finished because of these problems.. (I forget and try and fast forward the commercials)
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#4
Well... I might have lied before.. IF you start a recording that is currently recording. seeking should work (atleast backwords). It's only if you start it from LiveTV folder it won't be seekable.
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#5
I don't know about you guys, but I've been finding that I can't seek in most of my mythtv recordings. Either using myth:// or just SMB share to the Myth .mpg files.

I get log entries like:

DEBUG: Seek - seek to pos xxxxxxx, whence xxx
(from memory - don't have log here atm..)

where the pos value keeps increasing, and the video stops dead, until I back out to the menu.

It works on the XBox, but not from my Linux boxes. Is this an mplayer/dvdplayer issue? I remember reading something about the Xbox uses Mplayer by default, but XBMC on Linux uses the dvdplayer.

Any ideas?
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