George made me watch https://www.youtube.com/watch?t=163&v=joKVyKf0obU and the duration of the video kept increasing after starting at what I assume is the correct length, ~1 h. The duration seemed to stop increasing at 4 h 51 min. I'm running nightly on Fedora 21 and these packages may be of interest: $ rpm -qa | grep ffmpeg gstreamer-ffmpeg-0.10.13-15.fc21.x86_64 ffmpeg-libs-2.4.10-1.fc21.x86_64 $ rpm -qa | grep gstreamer gstreamer1-plugins-good-1.4.5-2.fc21.x86_64 gstreamer-0.10.36-11.fc21.i686 gstreamer1-libav-1.4.5-1.fc21.x86_64 gstreamer-plugins-bad-free-0.10.23-24.fc21.x86_64 gstreamer-plugins-base-0.10.36-12.fc21.x86_64 gstreamer1-plugins-bad-free-1.4.5-2.fc21.x86_64 gstreamer1-plugins-base-1.4.5-1.fc21.i686 gstreamer1-1.4.5-1.fc21.x86_64 gstreamer-plugins-good-0.10.31-13.fc21.x86_64 gstreamer1-plugins-bad-freeworld-1.4.5-2.fc21.x86_64 gstreamer-plugins-base-devel-0.10.36-12.fc21.x86_64 gstreamer-0.10.36-11.fc21.x86_64 gstreamer-devel-0.10.36-11.fc21.x86_64 gstreamer1-1.4.5-1.fc21.i686 gstreamer1-plugins-base-1.4.5-1.fc21.x86_64 gstreamer-plugins-base-0.10.36-12.fc21.i686 gstreamer-plugins-espeak-0.4.0-5.fc21.x86_64 libnice-gstreamer1-0.1.7-1.fc21.x86_64 PackageKit-gstreamer-plugin-1.0.6-1.fc21.x86_64 gstreamer1-plugins-ugly-1.4.5-1.fc21.x86_64 gstreamer-plugins-ugly-0.10.19-18.fc21.x86_64 gstreamer-ffmpeg-0.10.13-15.fc21.x86_64 gstreamer-tools-0.10.36-11.fc21.x86_64
For what it's worth, I can reproduce this as well on Fedora 21, but not on Windows or OS X. It only happens with the HTML5 youtube player.
Oh yeah, I forgot to say that I'm using the HTML player (I don't have flash installed).
I reported a similar problem a few years ago: Bug 948155. The URL in that bug is no longer valid, but I still have the file saved locally.
(In reply to Trevor Rowbotham from comment #3) > I reported a similar problem a few years ago: Bug 948155. The URL in that > bug is no longer valid, but I still have the file saved locally. Thanks, I didn't see that while filing this bug. I'm not sure it's the same thing, though, as my issues appears to be Linux-specific and yours seems Windows-specific. Let's leave them unduped for now but that's easily fixed if I'm wrong.
My guess would be an issue in the gstreamer-0.10 backend. Bug 948155 relates to MP3 which is different enough.
I'm having the same issue here, on Arch Linux using Firefox Beta. It doesn't look like a backend issue to me, since it only appeared on the 41 betas (I double-checked by downgrading again). It happens with all HTML5 videos, not only Youtube, and I can confirm it doesn't happen on Windows.
likely a dupe of bug 1180214