Cinelerra on FC6 working well and more YouTube-ness

I spent all day yesterday editing and rendering video using the Cinelerra install on my Fedora Core 6 box. I am happy to report that after about 10 hours, 15 projects and two or three times as many renders, Cinelerra did not crash once! Now, the types of activities I performed did not vary that much:
- open hour long DVD resolution video
- select five or ten minute long sections of video
- compensate for audio sync problems using nudge
- render out to YouTube compatible format (ala my previous post)

My previous Cinelerra install on Core 4 had crash problems as well as strange audio synchronization problems. One major difference between the systems is that my FC4 Cinelerra system had OpenGL enabled. My new FC6 system does not have OpenGL enabled. On FC4, I noticed that enabling OpenGL seemed to cause the instabilities mentioned above, though I was never able to prove it. Also, the more unstable projects tended to be projects that I had previously created. So as a test, I am recompiling Cinelerra on FC6 using OpenGL and will perform some edits on both old and newly created projects to see if the OpenGL version of Cinelerra is as stable as the non-OpenGL, X11 XV version on FC6. I am hoping that the latest NVidia drivers for my 7600GS 512MB card in combination with various bug fixes in FC6 will allow me to run Cinelerra on FC6 without crashes.

I have uploaded the results of yesterday's rendering session to my new YouTube account here:
http://www.youtube.com/profile?user=snufflerstormpig

I'm learning more about YouTube. It is a really rich environment for social interaction. Everybody has seen a YouTube video and peoples comments beneath it. But depending on how the content producer has configured the video, people can comment upon it by using a video response. Pretty cool. Also, most people know that you can embed a YouTube video into any web page simply by selecting the Embed code that appears on every page that displays a YouTube video and integrate that code into your web site. It looks like this:
<object width="425" height="350"><param name="movie" value="http://www.youtube.com/v/cW8EL2RgAEg"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/cW8EL2RgAEg" type="application/x-shockwave-flash" wmode="transparent" width="425" height="350"></embed></object>

Some of the more interesting stuff is not as evident. For example, if you are a content producer, you can create a "Channel", basically a home page of your profile like in the above link so that people can see your accumulated work. As a member (content producer or regular viewer), you can create playlists of your favorite videos and share them with your friends. When someone gets one of your playlists, they can play all the videos in that playlist simply by clicking once. Here is a playlist I created from the videos I rendered yesterday:
http://www.youtube.com/view_play_list?p=021BB1E61A3BFD19

Also, people can subscribe to your Channel (Subscribers) or you can make Friends who also like your videos. The difference between the two seems to be that Subscribers are more passive viewers of your content and Friends are content producers themselves, or at least have a more well defined profile created on YouTube. YouTube can automatically alert both of these two different types of people when you've uploaded new videos.

Anyway, granted I am a little late to the YouTube game, but I think a lot of other content producers are too. They should take advantage of this great experiment in social networking and get their hard work up on YouTube to show the rest of the world.

trials of Cinelerra rendering, deja vu all over again

Well, four hours of overnight rendering yields a video I can't playback. I get this error:
int YUVStream::read_header(): y4m_read_stream_header() failed: bad header magic
int YUVStream::open_read(char*): Bad YUV4MPEG2 header: parameter out of range

Now what the F is wrong? Is it a problem with:
- my rendering options I chose?
- this version of ffmpeg in general?
- my project?

I wasted a number of hours on the first two possibilities. I finally saw two issues in my project:
1) for some reason, probably my big fat fingers, an audio transition was placed right at the beginning of the project (Timecode 00:00:00). I deleted this.
2) I noticed that for joins between separate videos on the same a/v tracks, the joins between the audio and video segments did not end at the exact same place:
http://content.serveftp.net/video/avmisaligned.png

To stop this, I went to the end of each segment, zoomed in all the way, and made sure that each video and audio segment ended at the exact same time. If they didn't end at the exact same time, I clipped off a bit of whatever audio or video track is dangling by using the mark in/mark out indicators and doing a "cut". After doing the cut, the segments aligned perfectly.
Even with these changes, however, I still get a similar version of my original error when I load the project:
int YUVStream::read_header(): y4m_read_stream_header() failed: bad stream or frame header
int YUVStream::open_read(char*): Bad YUV4MPEG2 header: parameter out of range
However, I can output it to a usable format, so I don't mind the rather ugly error messages. You'd thought I would have known better by now. ARGH!

Along the way tonight, I've been trying to help the Cinelerra CVS community debug a couple of errors:
1) the intermittent project hangs
2) MS MPEG4 render crashes

I synchronized my hvirtual directory twice and recompiled, once for v932 for the project hang problem and then v940 for the MS MPEG4 render crashes. Both took a couple interations, but it seems like the programmers have the problems licked. That's good. We've been pushing them pretty hard lately.

So, finally around 11pm, I've rendered the video to a usable DVD mpg. Now it's time to render once more; this time to iPod format. It looks like FFMPEG has removed the "-b" bitrate switch in favor of some quality scale switch, "-qscale". The higher the qscale, the lower the quality. To create videos with the same quality as the original, you can use the "-sameq" switch. Otherwise, a qscale of 4 will yield a decent quality video with some significant compression. I'd use h264, but I haven't been able to install it successfully. I may try VLC..

Update 2009/06/09
My understanding of the "-sameq" switch was a little naive. Robert Swain enlightens here:
http://rob.opendot.cl/index.php/2009/05/01/bit-rate-file-size-quality-misunderstandings/

You'll probably need to read it a couple of times like I did.
:)
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