dvr-ms header states NTSC resolution although its stream is PAL

Discussion in 'Windows Media Player' started by Davor, Jan 7, 2009.

  1. Davor

    Davor Guest

    Summary: When capturing from TV to dvr-ms-file via Win XP MCE 2005, the
    header of the dvr-ms file signifies that the stream’s resolution is 720x480,
    while the contained stream resolution is 720x576, MCE configured for PAL
    country and Hauppauge 150 MCE a PAL version. This can have complications for
    playback.

    For example, when playing back in WMP (directly or through avisynth) with
    ffdshow as MPEG2 decoder, the lowest part of the picture (I assume some
    576-480 = 96 lines) is missing. When I consult the ffdshow info and/or
    avisynth’s info()-function it says the resolution is 720x480. When I switch
    back to my old nvidia decoder, the picture is displayed correctly in WMP and
    in file-preferences the correct 720x576 resolution is displayed. This led me
    to investigate the real resolution of the stream. After consulting various
    websites and making sure my Hauppauge MCE150 was configured correctly (i.e.
    to capture in PAL format), I went on to investigate the file itself. Gspot
    said it was an asf container, so I downloaded asfviewer
    (http://www.microsoft.com/windows/windowsmedia/forpros/format/ASFViewer.aspx)
    and opened the dvr-ms file. Under Header object “Stream Properties†one finds
    the following data:

    Stream Properties Object [1] (297 bytes)
    Property Value
    File Position 9005 ( 0x232D )
    Object ID B7DC0791-A9B7-11CF-8EE6-00C00C205365
    Object Size 297 ( 0x129 )

    Stream Number 1
    Version 1
    Offset 0
    Encrypted False
    Security ID 18873916 ( 0x11FFE3C )
    Stream Type Specific
    Stream Type Video Media
    Window Width 720
    Window Height 480
    Flags 2
    Bitmap Info Header
    biSize 208
    Width 720
    Height 480
    Planes 1
    Bits 0
    Compression TEXT: DVR
    0000: 44 56 52 20 DVR
    Image Size 0
    X Pels / Meter 0
    Y Pels / Meter 0
    Colors Used 0
    Colors Important 0
    Extra Data Size 168
    Extra Data 0000: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00

    0010: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00
    0020: 00 00 00 00 00 00 00 00-63 17 05 00 00 00 00 00 c
    0030: 00 00 00 00 00 00 00 00-04 00 00 00 03 00 00 00
    0040: 00 00 00 00 00 00 00 00-28 00 00 00 D0 02 00 00 (
    0050: E0 01 00 00 01 00 00 00-4D 50 45 47 00 00 00 00 MPEG
    0060: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00
    0070: 00 00 00 00 00 00 00 00-02 00 00 00 02 00 00 00
    0080: 00 00 00 00 00 00 00 00-D0 C4 C4 C4 49 00 2B 4E I +N
    0090: 98 FB 95 37 F6 CE 51 6D-D1 C4 C4 C4 49 00 2B 4E 7 Qm I +N
    00A0: 98 FB 95 37 F6 CE 51 6D 7 Qm

    This led me to try to change the headerdata (all instances of 480 to 576)
    and see whether this is causing the playback problems. After I changed the 3
    values (those emphasized), the ffdshow codec stated displaying the dvr-ms
    file correctly (with lower part of the picture displayed and acknowledging it
    as a 720x576 stream) Further testing showed that changing only the binary
    data under “extra dataâ€-property from “E0 01†to “40 02†was enough to make
    the dvr-ms file play correctly with ffdshow in WMP.
    When I tried to play the modified file in MCE, there was no problem in
    picture quality, except the picture was stuttering. (As if the “fps†didn’t
    match with the refresh rate.) I have no explanation for the stuttering.

    I need this to work with ffdshow because nvidia decoder doesn’t work with
    avisynth, and I need to use avisynth for a script I am writing to automatize
    transcoding dvr-ms to h264.

    So, the question is: am I the only one or is everyone having this issue AND
    IF SO, how can one force MCE to write down the header of dvr-ms-files
    correctly? Help would be appreciated.
     
    Davor, Jan 7, 2009
    #1
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