[mythtv-users] Patches that improve mythcommflag accuracy

[Carl Hunter]

On 10/28/2014 12:09 AM, faginbagin wrote:
> Hi Carl, I did not test recordings made using a PVR-150, but I can. 
> All the recordings I tested were recorded using an hdhomerun. I think 
> my sister still has quite a few old recordings from a PVR-150. These 
> would have been made on 0.23. I've also got a couple of HVR-1600 
> tuners which have both analog and digital tuners. The analog side of 
> the HVR-1600 uses the same kernel driver, ivtv, as the PVR-150, and as 
> far as mythtv is concerned, they look the same. I haven't used the 
> analog side in a couple of years, but I might try configuring one. 
> I'll get back to you on what I learn. Just to confirm what I think 
> should be obvious: the recording that mythcommflag can't handle is one 
> you can play back without any problem in mythfrontend, right? Can you 
> tell me how you've configured your PVR-150s in mythtv-setup? I seem to 
> recall that, in 0.23, mine were configured to record video at 720x480 
> resolution with VBI enabled and variable bit rate around 2.4 Mbps, and 
> audio was mp2 192 Kbps. Perhaps changing your card's configuration in 
> mythtv-setup will let you record content that mythcommflag can decode? 
> Regards, Helen 

I did some checking and found the following from mediainfo when run on 
the recording I've been testing with.

General
Complete name                            : 
/var/lib/mythtv/recordings/1306_20140918170000.mpg
Format                                   : MPEG-PS
File size                                : 1.08 GiB
Duration                                 : 29mn 57s
Overall bit rate mode                    : Variable
Overall bit rate                         : 5 172 Kbps

Video
ID                                       : 224 (0xE0)
Format                                   : MPEG Video
Format version                           : Version 2
Format profile                           : Main at Main
Format settings, BVOP                    : Yes
Format settings, Matrix                  : Custom
Format settings, GOP                     : M=3, N=15
Duration                                 : 29mn 57s
Bit rate mode                            : Variable
Bit rate                                 : 4 685 Kbps
Maximum bit rate                         : 6 000 Kbps
Width                                    : 480 pixels
Height                                   : 480 pixels
Display aspect ratio                     : 4:3
Frame rate                               : 29.970 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan order                               : Top Field First
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 0.679
Time code of first frame                 : 00:00:00:00
Time code source                         : Group of pictures header
Stream size                              : 1 004 MiB (91%)

Audio
ID                                       : 192 (0xC0)
Format                                   : MPEG Audio
Format version                           : Version 1
Format profile                           : Layer 2
Duration                                 : 29mn 57s
Bit rate mode                            : Constant
Bit rate                                 : 384 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 KHz
Compression mode                         : Lossy
Delay relative to video                  : -211ms
Stream size                              : 82.3 MiB (7%)

I believe I've since set the resolution to 720x480 but get the same 
results.  All my SD recordings play fine in mythfrontend.  I've also 
have a mix of PVR-150's and PVR-1600's.  I'm pretty sure this recording 
came off a PVR-150 though.  In my testing mythcommflag from myth 0.24 
finds 3 commercial breaks while 0.27 finds none on this recording.

Thanks

Carl