The VideoLAN Forums

I'm a student involved in a successful secular student group wherein we recently recorded all of our videos and streamed them live. The local copies were all produced as .flv containers with "Codec: H264 - MPEG-4 AVC (part 10) (avc1)" as the video codec and "Codec: MPEG AAC Audio (mp4a)" as the audio codec. All of the files except one were easily converted to MP4 containers for editing in Adobe Premier Pro (adding intro and outro splash screens and the like).

The one exception plays fine in VLC, Windows Media Player, and other media players I've tried, however transcoding via VLC to another video codec or editing the video in Premier Pro causes the audio and video to go out of sync. It appears the issue is due to some video corruption toward the beginning, including some frames that appear in VLC with a large amount of green corruption and appear to freeze while the audio continues fine. This has affected our ability to upload our final keynote speaker's video because manually synchronizing the audio and video is troublesome and I think the issue is due to some corruption handled correctly on playback but not on transcoding. I've tried:

• Transcoding the video to MPEG-2 in VLC, as well as re-encoding in H-264, as well as Adobe Media Encoder.
• Changing the container format to MPEG-TS, MP4, and separately as an MPEG-2 encoded AVI video and MP3/WAV audio stream.
• Transcoding the video and audio into separate streams to then align in Premier Pro.
• Using the "streaming" functionality as opposed to converting in VLC to create a new container using the above.
• Using the start-time setting in VLC to skip past the apparent corruption.
• Trying most of the above in Adobe Media Encoder.

Given all of this, we really, desperately need an expert to help us know the command-line fu that might allow us to encode this video correctly. We've no idea why the video plays fine in VLC, but attempts to edit and transcode consistently cause the audio and video to go out of sync. I am not certain, being a layman in A/V technologies, but I think part of the issue is from a change in the transcoded/format changed video's frame rate. The original video was 25fps, and every other video we changed container format on came out as 25fps. However, the "broken" video when converted to mp4 container shows as "Frame rate: 17.663138" and when attempting to transcode to 25fps, it ends up in the ~19fps range.

So, please halp. I'm close to exhausting my ability to try different things to salvage this video, which is our recording of the eminent theoretical physicist and cosmologist Lawrence Krauss delivering the latest version of his talk "A Universe from Nothing" to our student body.

Cut the video corruption with virtualdub or avidemux or handbrake.

Thank you very much, Handbrake did the job.