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Problem with recording analog video output - Copy Protection

Adi Aharon
Prodigy 40 points

Hi,

Our product is OMAP3530-based video board, produces standard video output (PAL/NTSC formats). Recently, two of our customers complained about having "Copy protection" messages while trying to record video by using their digital video recorders.

Looking at the processor spec (spruf98p.pdf) I could not find anything related to this phenomena. The only reference to copy protection appears on the page 2264 and says: "For a complete description of copy protection including CGMS-A, please refer to CEA-608-x standard"

It's worth to notify we could not reproduce this issue with our DVR, we use to capture analog video, it works and does it job without any "protection" messages.

Please help me to find  the reason for this issue.

Thanks,
Adi

  • 0
    Prodigy 40 points

    Hi,

    Just to update the community..

    The reason for "Copy protection" issue, described above,  was found. Video copy protection is controlled by WSS (Wide-screen sigalling) data, programmed by  the VENC_BSTAMP_WSS_DATA[27:8] WSS_DATA bit field. WSS is controlled by DSS.VENC_L21_WC_CTL register

    Kernel initializes values of copy-protection bit, VENC_BSTAMP_WSS_DATA[21] to 0, but the value of WSS invertor (DSS.VENC_L21_WC_CTL[15] INV) to 1. As a result - the WSS data, embedded by the encoder within the vertical blanking interval is 1. This causes DVR to raise "copy protection" message and prevent analog video recording

    It is worth to notify that old DVRs simply ignore this part of WSS data and do not implement copy protection management, as defined by CGMS-A standards

    For more info - see http://en.wikipedia.org/wiki/CGMS-A

    Thanks,
    Adi