Hans Verkuil wrote: > On Friday 19 October 2007 21:52:15 Duncan Webb wrote: >> Hans Verkuil wrote: >>> On Friday 19 October 2007 19:30:59 Duncan Webb wrote: >>>> Hans Verkuil wrote: >>>>>> Hi all, >>>>>> >>>>>> To embed a teletext VBI stream in the mpeg file, is it just a >>>>>> case of calling v4l2-ctl with: >>>>>> --set-fmt-sliced-vbi=teletext and >>>>>> --set-ctrl=stream_vbi_format=1 >>>>>> or do I need something else as well? >>>>> No, that's it. For PAL you usually want to capture the wss signal >>>>> as well, so I would do -set-fmt-sliced-vbi=teletext,wss. >>>> Thanks, why do you embed the wss data, are there any players that >>>> use it? >>> The PVR-350 output uses it: if you playback a file with embedded >>> WSS signals, then those will be reproduced on the TV-out, >>> automatically switching the TV to widescreen. >> Okay cool, but aren't the play back capabilities are a bit limited? > > For PAL you're missing out on teletext for the subtitles, yes. But most > people don't need that. The WSS signal is something I find very handy > though as I would otherwise have to switch my TV between 4x3 and 16x9 > manually. Teletext output support is not normal for these types of > cards, probably only really high-end cards can do that.
That's why I use mplayer, extracting the subtitles first or during the recording and playing them back. >>>> AFAIK mplayer can't process the ivtv packets, which is very >>>> annoying when I've recorded a 16:9 mpeg and mplayer shrinks it >>>> vertically. The video_aspect control does work correctly, just >>>> that I don't yet set it when the wss signal indicates 14:9 or 16:9 >>>> (working on this). >>> The video_aspect of most 16:9 broadcasts should still be 4:3 >>> (unless it is an anamorphic broadcast). The captured picture is 4:3 >>> because of the black bars. >> What do you mean by black bars? > > If you record widescreen TV is it really a 4x3 image with black bars at > the top and bottom (to be backwards compatible with old 4x3 TVs). The > MPEG stream contains those bars as well so the picture is still in 4x3 > aspect. Of course, you don't see the black bars. Do sometimes see white dots at the sides, which are sometimes the whole height of the video. I find it still a bit strange that mplayer behaves the same with or without the letterbox bars. But this is not an ivtv problem. >> So that I could randomly play the episodes I made a mistake >> re-encoding a DVD to mpeg, yes I know DVDs are mpegs, by setting the >> 4:3 bit in the stream. > > DVDs often use anamorphic widescreen, which has no black bars and I > believe for these streams the video_aspect is indeed 16x9. > >> While everything was correctly proportioned mplayer shrunk the video >> vertically and ignored the monitor aspect. The same applies to any >> 16:9 that has been recorded with the 4:3 bits set. >> >> So I'm guessing that setting the 16:9 bit, recording will play >> correctly. > > I don't believe so, but I can't test it at the moment. I'll let you know. >> Where is IVTV_IOC_S_GOP_END defined, can't find its definition only >> V4L2_ENC_CMD_STOP_AT_GOP_END. The ivtvctl program still uses it so I >> guess that it still works. > > Ah, you're a good tester: that was a bug in the usage message of > ivtvctl. I've fixed that. IVTV_IOC_S_GOP_END is also in ivtv-functions.h > The old IVTV_IOC_S_GOP_END has been removed. Instead use the new > VIDIOC_ENCODER_CMD and VIDIOC_TRY_ENCODER_CMD ioctls if you want this > feature. See the v4l2 spec for more details. I'll put my glasses back on. What the best way to access external controls like "Video Aspect", using the id or the name? I'm guessing that the name is best from the code I've seen but an id would be more normal Thanks Duncan _______________________________________________ ivtv-devel mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-devel
