WinTV7 SoftPVR MPEG-2 Field Flag Setting

[DonRB]

I am using a model HVR-1250 with WinTV7 (latest version) to record from analog channels and s-video sources to MPEG-2 format. I then use other software to make a recordable DVD or transfer the video to a flash drive for playback on the popular Western Digital WDTV-Live hardware media player connected to an HDTV.

I've found that the WinTV7 SoftPVR recorded .ts video files are in MPEG-2 interlaced format with top field first, however the flags apparently are set for bottom field first. This non-matching flag setting apparently causes some MPEG-2 decoders/deinterlacers (including that used in Windows Media Player) as well as some standalone playback devices that follow the flags to display the video with "jitter" due to improper field order on display. Some other decoders ignore the flags and can play the video properly such as the one used in WinTV itself. For good compatability with these interlaced MPEG-2 videos with all types of software decoders and external playback devices and DVD players, setting the flag to top field first to match the actual field order used is needed however.

I can demux the .ts videofile manually and restream the video (without reencoding) to change the field flag to the proper top field first setting and then remux with the audio for a new .ts or .mpg file. This video will then play properly with software and devices that follow the flags.

It would be a lot easier and the MPG-2 videos created from analog video sources would be more compatable if WinTV7 could set the flag properly to top field first however. Is this a setting passed to SoftPVR that could be changed for a future update?
I'm sure it would be very much appreciated by those users of the WinTV cards that use the WinTV7 SoftPVR MPEG-2 encoding from analog video sources.



On a separate matter, I installed the latest WinTV7 under Windows 7 x64 and noted the ODBC installation problem that is discussed in other older threads on this forum. I managed to fix the ODBC database manually as suggested in one of those threads. But would it be possible for the installer to be updated in future WinTV7 updates to do that properly automatically during installation on a Windows 7 x64 OS system?

Once installed with that fix, WinTV7 has been running reliably for me and I prefer it over Windows Media Center for regular TV viewing and recording too.

[TheNewGuy]

If you look in your PCI.txt log file do see either a "Setting bottom field first" or "Setting top field first" message. With NTSC devices you should see "Setting bottom field first" in the log.

[DonRB]

I checked on my setup, but no pci.txt log is created, that file is always empty.

In any case I have determined that the flag state in the WinTV produced .ts file from a recording from an analog NTSC video source is saying "bottom field first" from various MPEG-2 video utilities however the actual field order encoded by SoftPVR appear to be in the more common top field first order, since if I restream (without reencoding) using a free utility program which only changes the flag state to top field first it works perfectly in all cases I've tested with the modified file. It just takes extra work to demux the .ts file, restream the video file, and remux back to .ts or .mpg format. It would be much easier if SoftPVR could set the top flag state itself properly in a future update.

So what happens is that some MPEG-2 decoders that go by what the flag says (such as that used with Windows Media Player) and many external DVD and media players, but since the fields are actually encoded apparently in top field first order it causes jittery playback in those cases. With other MPEG-2 decoders (such as the one used by WinTV itself for playing back a video file) that ignore the field flag state apparently and properly play the file in top field first order for display, no jitter in that case.

What would be great is if WinTV can get SoftPVR to continue encoding the fields in top field first order but also set the flag to match that state, top field first. Perhaps that is set by a parameter that WinTV passes to the SoftPVR encoder?

I'm using the HVR-1250 card that is a PCI-Express board without hardware MPEG encoding, so WinTV must use SoftPVR for analog video recording. I assume that with the card models that have onboard MPEG encoding and don't use SoftPVR to encode that the field flag may be correct with such cards. Thats why I hope its something that can be configured by WinTV to SoftPVR that could be changed for a future update of the software.

[TheNewGuy]

I checked on my setup, but no pci.txt log is created, that file is always empty.

I forgot to mention you'd need to turn on extended logging in WinTV then reboot.

[TheNewGuy]

What would be great is if WinTV can get SoftPVR to continue encoding the fields in top field first order but also set the flag to match that state, top field first. Perhaps that is set by a parameter that WinTV passes to the SoftPVR encoder?

The log messages I refer to above were showing what the app was telling the SoftPVR encoder to use.

[DonRB]

I forgot to mention you'd need to turn on extended logging in WinTV then reboot.

OK I did that and did a quick analog NTSC channel recording.
I found this section in the long pci.txt log file that was generated:

2011-04-29 14:10:00.699 BaseAnalogSoftPVRGraph::ConfigureEncoderProfile() get_TVFormat() returns 0x00000001
2011-04-29 14:10:00.699 Setting bottom field first
2011-04-29 14:10:00.699 Setting encoder video format to NTSC

[DonRB]

The log seems to confirm that bottom field first order is requested by WinTV to SoftVTR?

I have confirmed the flag in the generated .ts mpeg-2 video file indeed indicate bottom field first. However, the problem is that the NTSC analog recorded video file data actually seems to be encoded in top field frame first order from my tests, though the flag says bottom field first order. The mismatch between the actual field order and the flag causes problems on playback on some mpeg-2 decoders resulting in a jittery display.

If WinTV simply requests bottom field first to the SoftPVR application, might it be that its SoftPVR thats encoding with top field first anyway, and only setting the flag to bottom field first in that case?

Is it possible to as a test to get WinTV for a NTSC analog recording to request top field first (instead of bottom field first) to SoftPVR and see what format .ts file is produced? That might produce an interlaced mpeg-2 file that would play properly with various mpeg-2 decoders (like used with windows media player) and various DVD/media player hardware.

[DonRB]

Mr. X, can you please check into the WinTV7 SoftPVR MPEG-2 recording field flag setting issue?
The mpeg-2 video data appears to be encoded in the common top field first order, but the flag is in the bottom field first order state, also confirmed in the pci.txt log entry.

If the flag in the mpeg-2 video is changed to the top field first after recording via a utility program that does a restream without re-encoding, the video will then play fine with decoders that follow the flags such as that used by Windows Media Player in Windows 7.

Hoping that in a future WinTV7 release both the data and the flag can match for top field first order, allowing direct compatability for mpeg-2 recorded analog video with external media players.

[DonRB]

Any update on getting WinTV7 using SoftPVR on analog video input to set the MPEG-2 field flag properly for top-field first in a future version release?

[Mr X]

can you explain step by step how you are doing this:

£I have confirmed the flag in the generated .ts mpeg-2 video file indeed indicate bottom field first."