NBC.com FLV Conversion keeps going out of sync

[tbfl]

I have used Applian's Replay Media Catcher to capture an episode of The Black Donnelys from NBC.com in FLV format. I have attempted in several ways to convert the FLV to an XVID avi file, but every method I have used has resulted in a major Audio/Video synch issue.

The first FLV file from the pilot (Episode 1 Part 1) - when I play the FLV file in either VLC or FLVplayer it shows this clip to have a running time of 2:46 and everything plays perfectly.

I used FFMPEG to convert the file to an XVID AVI using:

ffmpeg -i e1p1.flv -vcodec mpeg4 -vtag XVID -b 800 -acodec mp3 -ab 48 Part1.avi

This results in an AVI with a running time of 2:29 that quickly goes out of synch.

I tried extracting the audio only as an mp3 file using:

ffmpeg -i e1pe1.flv -ab 48 Part1.mp3

This results in an mp3 file with correct running time of 2:46.
I then tried to extract only the video portion using:

ffmpeg -1 e1p1.flv -an -vcodec mpeg4 -vtag XVID -b 800 Part1.avi

This again results in the full video showing a running time of only 2:29 and will not synch up with the audio only file.

GSPOT shows the original FLV file to be the FLV4/VP62 codec with "Codec Status Undetermined" and a frame rate of 33.367

I have attempted the same conversion in SUPER with and without directshow enabled, resulting in the same out-of-synch issue. I attempted pulling out the Audio and Video with FLVextract and it results in the same thing - mp3 at 2:46 and AVI video at 2:29.

I attempted to convert using RIVA - out of synch. I tried the Moyea FLV converter - same result.

I tried to convert the FLV straight to a VOB file in ConvertXtoDVD and get the error message that it "is unsupported or not A/V file."

Out of pure desperation, I attempted to use the Streaming/Transcode feature of VLC. I chose to transcode video using the MPEG-4 Video codec and to transcode Audio using the MPEG 4 Audio codec. This resulted in an MP4 file that is 4 times larger than the original FLV file with the shorter running time of 2:29, but the audio and video remain in synch from beginning to end.

GSPOT shows this new file to be mp4v video codec with mp4a MPEG-4 AAC for audio with the frame rate of 33.367

I have attempted to again convert the new MP4 file in ConvertXtoDVD, but it resulted in the same original out of synch issue. Attempting to convert the new file in ffmpeg results in the same out-of-synch issue. FFMPEG identifies the MP4 file as now having framerate of 25 when GSPOT says it is 33.367

Any further advice/suggestion/correction is greatly appreciated...

[Baldrick]

Sounds like a video with variable frame rate (VFR).

Try transcode to some other format in VLC, like mpeg2 with mpg2 video and mpga audio.

Or wait for the dvd release...

[tbfl]

Tried the MPEG transcode....odly it synched up fine when I played it back in VLC....but playing it in MPLAYER or FFPLAY causes synch errors again....

I went so far as to submit the file to www.media-convert.com....again out-of synch was the result...

Any tips for dealing with Variable Frame Rate video ?

[jagabo]

I'd try AVISynth's DirectShowSource() with the fps and convertfsp arguements:

DirectShowSource("path\to\file.flv", fps=23.976, convertfps=true)

Replace 23.976 with the frame rate of the FLV file.