Hiya. Just to emphasize some key points alluded to in Bernhard's response:
>> My understanding is that in the US NTSC is broadcast bottom field >> first. Thus, the TV will display the bottom field, then the top field. >> I am caputring from a US broadcast. Now the bttv driver alledgedly >> delivers frames top field first, although streamer doesn't set the A broadcast is pretty much just alternating fields --- like Bernie said, it's the framegrabber makes the choice of starting with a top or a bottom field when it begins the capture. (On a good day, the driver has some say in making that choice.) >> interlacing tag in the yuv4mpeg header. Consequently, I set the >> interlacing flag to "top field first" in the yuv4mpeg header when I pipe >> the yuv file into mpeg2enc. Now mpeg2enc has an option >> "--playback-field-order" which can be set to play bottom field or top By default, mpeg2enc gets the field order from the interlacing flag in the YUV4MPEG2 header. "--playback-field-order" is used to override the header, but you have already set the header correctly <fingers crossed>, which is the best approach since it provides correct info to any other tool in the chain as well. >> field first. Should I be setting this to bottom because bottom fields >> are broadcast first in the US, and hence should be played first? Nope... whatever is playing the MPEG will start with whatever field is specified in the MPEG, and the resilient TV won't care. >BTW2: I'll add a short description of the -z|--playback-field-order b|t >option to the manpage of mpeg2enc. Because it is missing. (Maybe there could be a mention that the default order is read from the stream header? In most cases, use of this option should be unnecessary.) -matt m. ------------------------------------------------------- This SF.net email is sponsored by: Perforce Software. Perforce is the Fast Software Configuration Management System offering advanced branching capabilities and atomic changes on 50+ platforms. Free Eval! http://www.perforce.com/perforce/loadprog.html _______________________________________________ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
