On Sun, 2010-11-14 at 16:05 -0600, Richard Pickett wrote:
> Updating on previous findings.
> 
> 
> Using Pitivi 0.13.5
> 
> 
>                 
>         1. (preview cuts off mp3 tracks): When playing the voice-over
>         (mp3) segment in the "preview" to line up the timing of the
>         end of the voice-over with the next video, the voice-over gets
>         cut off at the end, when I play the mp3 on any other play it's
>         end is "normal". This concerned me and I figured we may be
>         back to the same kind of problems I discussed in my last
>         email, so I didn't produce the voice-over videos, I just
>         wanted to test how the rendering would come out. I rendered
>         the project with one white background image and just the video
>         from the two segments that already had video. Here's a
>         screenshot of the
>         timeline: http://www.csrtechnologies.com/Screenshot.png
> 
> 
> On other projects, this problem still exists. When previewing a
> project (pre-render) the mp3s get chopped off (the sound of the mp3
> stops before the actual mp3 recording ends). Playing the mp3 on any
> other player and you hear all the way to the end of it. Just not in
> pitivi.

  Those mp3s might be VBR without a header file, meaning the duration
estimation done when importing the file is completely wrong.
  One way to fix such files is to remux them to have the proper header.

  gst-launch-0.10 filesrc location=original.mp3 ! id3demux ! mp3parse !
xingmux ! id3v2mux ! filesink location=fixed.mp3

  mp3parse might have been renamed to mpegaudioparse if you have latest
gst-plugins-bad.

  The resulting file will have accurate duration.

> 
> 
>         2. (rendering video speed varies): Well, everything "works"
>         with the exception of the two videos that were inserted. When
>         they go to play (in the final rendered video), their audio is
>         the right speed but the video playback is too fast, it
>         actually ends and sits on the white background for a little
>         while before the next mp3-only segment picks up. I just
>         noticed that I accidentally didn't use the original video when
>         inserting those two video segments, so I'll be trying it with
>         the original and see if it makes a difference. One thing to
>         note, the final is 25fps and the two inserted videos were
>         15fps. Both are flv, my thought here is maybe the "render"
>         code just copied the frames frame-for-frame out of the
>         inserted videos into the final and naturally ran out of frames
>         because of the frame rate difference.
> 
> 
> This problem turns out to be a real problem for pitivi. If your source
> video is 15fps and you are rendering a 25fps video, it doesn't create
> any tween frames to fill the other 10 frames needed per second. So a
> 10 second 15fps video has 150 frames, and when you render that into a
> 25fps video the video will all be gone in 7 seconds (150 frames /
> 25fps).

  GStreamer (and therefore PiTiVI) doesn't care about framerates for
rendering, it uses timestamps for that. The number of frames is
completely irelevant... unless there's a bug in an encoder/muxer... but
I seriously doubt that.
  PiTiVi *will* create/drop frames to conform to the target framerate
(by using the videorate gstreamer element).

  Can you file the most minimalistic timeline reproducing the problem
and file a bug with a link to the project/sources ?

> 
> 
> 
> 
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