Unable to stream without transcoding?
Posted: 21 Apr 2005 08:03
Howdy,
I solved my own question about getting a stream going with my ATI "TV Wonder Elite" card after much fiddling around (details here: viewtopic.php?t=8762 )
But, my "solution" reeks of "workaround". I was only able to get the stream working by selecting both the audio and video transcode options in the Stream settings window. Otherwise, the server simply sent no data.
This card is a hardware MPEG-2 encoder, which I bought specifically so that I could simply stream NTSC MPEG-2 over my network while not loading down the CPU in the PC with compressing raw video from a capture card.
However, even if I select "mp2v" and "mp2a" audio codecs (the format the video should already be in!) and an MPEG2 transport stream (my only choice for UDP), my CPU maxes out at 100% and is not quite able to keep up. I can get it to keep up by selecting a scaling factor of 0.5 on the video transcode, but this is still producing about 80% CPU usage and (obviously) reduced video quality.
It seems as though I should be able to stream the native, hardware-produced transport stream from this card without any intervention and with very little CPU overhead (maybe just formatting a transport stream).
One thing I notice -- when I start the stream and the various properties windows for my device pop up in sequence (I have to do these, apparently, so that I can select my S-Video input), the second dialog is "Stream Format". It has two sub-groups. One is for Video Format (whose contents seem correct -- NTSC_M Video Standard, 29.970 frame rate, YUY2 color space, 720x480 output).
The second is for Compression. It has an I Frame Interval and a P Frame Interval, as well as a Quality slider. But, these three are all dimmed out. I don't know how to interpret this -- are they dimmed because the hardware encoder is active? Or, does their being dimmed and un-set mean that the hardware encoder is disabled? Argh!
So, I guess I basically have one question: can it be done?
I solved my own question about getting a stream going with my ATI "TV Wonder Elite" card after much fiddling around (details here: viewtopic.php?t=8762 )
But, my "solution" reeks of "workaround". I was only able to get the stream working by selecting both the audio and video transcode options in the Stream settings window. Otherwise, the server simply sent no data.
This card is a hardware MPEG-2 encoder, which I bought specifically so that I could simply stream NTSC MPEG-2 over my network while not loading down the CPU in the PC with compressing raw video from a capture card.
However, even if I select "mp2v" and "mp2a" audio codecs (the format the video should already be in!) and an MPEG2 transport stream (my only choice for UDP), my CPU maxes out at 100% and is not quite able to keep up. I can get it to keep up by selecting a scaling factor of 0.5 on the video transcode, but this is still producing about 80% CPU usage and (obviously) reduced video quality.
It seems as though I should be able to stream the native, hardware-produced transport stream from this card without any intervention and with very little CPU overhead (maybe just formatting a transport stream).
One thing I notice -- when I start the stream and the various properties windows for my device pop up in sequence (I have to do these, apparently, so that I can select my S-Video input), the second dialog is "Stream Format". It has two sub-groups. One is for Video Format (whose contents seem correct -- NTSC_M Video Standard, 29.970 frame rate, YUY2 color space, 720x480 output).
The second is for Compression. It has an I Frame Interval and a P Frame Interval, as well as a Quality slider. But, these three are all dimmed out. I don't know how to interpret this -- are they dimmed because the hardware encoder is active? Or, does their being dimmed and un-set mean that the hardware encoder is disabled? Argh!
So, I guess I basically have one question: can it be done?
