[mythtv-users] Live TV recording file size double size of DVBViewer on Windows 7?

[David Crawford]

On 12 March 2012 00:42, Raymond Wagner <raymond at wagnerrp.com> wrote:

> On 3/11/2012 19:45, David Crawford wrote:
> > can anyone explain why the file sizes are different
> >
> > DVBViewer recording:
> > Video Bit rate                                 : 2 645 Kbps
> >
> > MythTV Recording:
> > Video Bit rate                                 : 4 004 Kbps
>
> Because they were recorded at two different times, during which the
> broadcaster's encoder was running using different parameters.  Both
> DVBViewer and MythTV are recording the video as it is sent by the
> broadcaster.  The broadcaster was simply sending more data during the
> show MythTV was recording.
>
> > and why one has teletext subtitles and the other no
> >
> > DVBViewer recording:
> > ID                                       : 512 (0x200)
> > Menu ID                                  : 4704 (0x1260)
> >
> > MythTV Recording:
> > ID                                       : 512 (0x200)
> > Menu ID                                  : 1 (0x1)
>
> My guess... it has something to do with the difference in this "Menu ID"
> value, however I don't know what that is.
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>

The Menu ID is the "Service ID" for that channel. (as seen here :
http://en.kingofsat.net/pack-skydigital.php). You can change things like
service ID and PID's easily in windows is there a way doing it with Myth?

Also, the reason for file size differences doesn't appear to be down to the
fact that the broacaster has changed anything as the filesize differences
seem to be pretty consistent over a large number of recoridngs made on 2
separate machines (1 DVBViewer and 1 MythTV). Below is the mediainfo of the
exact same program recorded on both, its seems that the Bits/(Pixel*Frame)
is where the difference lies . This time the subtitles were captured
though, strangely enough.

Myth Recording:

General
ID                                       : 2026 (0x7EA)
Complete name                            : Y:\mythtv\5704_20120312140000.mpg
Format                                   : MPEG-TS
File size                                : 956 MiB
Duration                                 : 29mn 43s
Overall bit rate mode                    : Variable
Overall bit rate                         : 4 497 Kbps

Video
ID                                       : 512 (0x200)
Menu ID                                  : 1 (0x1)
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=12
Codec ID                                 : 2
Duration                                 : 29mn 43s
Bit rate mode                            : Variable
Bit rate                                 : 4 081 Kbps
Maximum bit rate                         : 15.0 Mbps
Width                                    : 704 pixels
Height                                   : 576 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 25.000 fps
Standard                                 : PAL
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)                       : 0.403
Stream size                              : 867 MiB (91%)

Audio
ID                                       : 640 (0x280)
Menu ID                                  : 1 (0x1)
Format                                   : MPEG Audio
Format version                           : Version 1
Format profile                           : Layer 2
Codec ID                                 : 4
Duration                                 : 29mn 42s
Bit rate mode                            : Constant
Bit rate                                 : 192 Kbps
Maximum bit rate                         : 1 726 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 KHz
Compression mode                         : Lossy
Delay relative to video                  : -490ms
Stream size                              : 40.8 MiB (4%)
Language                                 : English

Text
ID                                       : 576 (0x240)-888
Menu ID                                  : 1 (0x1)
Format                                   : Teletext Subtitle
Language                                 : English

DVBVIEWER recording:

General
ID                                       : 2026 (0x7EA)
Complete name                            : X:\03-12_14-00-23_Sky News_Sky
News with Kay Burley - 30.ts
Format                                   : MPEG-TS
File size                                : 569 MiB
Duration                                 : 29mn 36s
Overall bit rate mode                    : Variable
Overall bit rate                         : 2 687 Kbps

Video
ID                                       : 512 (0x200)
Menu ID                                  : 4704 (0x1260)
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=12
Codec ID                                 : 2
Duration                                 : 29mn 35s
Bit rate mode                            : Variable
Bit rate                                 : 2 360 Kbps
Maximum bit rate                         : 15.0 Mbps
Width                                    : 704 pixels
Height                                   : 576 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 25.000 fps
Standard                                 : PAL
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)                       : 0.233
Stream size                              : 500 MiB (88%)

Audio
ID                                       : 640 (0x280)
Menu ID                                  : 4704 (0x1260)
Format                                   : MPEG Audio
Format version                           : Version 1
Format profile                           : Layer 2
Codec ID                                 : 4
Duration                                 : 29mn 35s
Bit rate mode                            : Constant
Bit rate                                 : 192 Kbps
Maximum bit rate                         : 1 726 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 KHz
Compression mode                         : Lossy
Delay relative to video                  : -450ms
Stream size                              : 40.6 MiB (7%)
Language                                 : English

Text
ID                                       : 576 (0x240)-888
Menu ID                                  : 4704 (0x1260)
Format                                   : Teletext Subtitle
Language                                 : English
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