Question regarding .flv output

[greenythebeast]

I'm not even sure this is the right website to ask this question but because it has something to do with rtmpdump I thought I'd ask anyway. When I use rtmpdump to download a live stream, I get a .flv file that is unseekable. From what I understand this is normal. So in order to make it seekable I use Handbrake to convert it into a .mp4. However, during this conversion something odd happens. The original .flv file is always 15 FPS. However, the converted .mp4 file is always less FPS. Sometimes it's only a few FPS but in some cases I've seen the FPS drop to 5. For example, with one file the original .flv had over 103k frames, however, the converted .mp4 file only had around 39k frames. Where are all of these frames disappering to? In Handbrake's log I get a lot of these lines:

sync: video time didn't advance - dropped 2 frames (delta 0 ms, current 617057820, next 617078880, dur 21060)

Is this something to do with how rtmpdump creates the .flv file? Thanks for any input.

[svnpenn]

HandBrake cannot remux without reencoding.

You should be using FFmpeg.

ffmpeg -i input.flv -c copy output.mp4

[greenythebeast]

Originally Posted by svnpenn

HandBrake cannot remux without reencoding.

You should be using FFmpeg.

ffmpeg -i input.flv -c copy output.mp4

I get this error when trying that:

[mp4 @ 0x101554600] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 462 >= 462
av_interleaved_write_frame(): Invalid argument

Any ideas?

[svnpenn]

Link the stream

or

Upload 10MB RtmpDump capture

so I can play with it.

[greenythebeast]

I think I figured it out. Used a different compiled binary of FFmpeg and it seems to work even though I get a lot of:

[mp4 @ 0x10101cc00] st:0 error, non monotone timestamps 134217 >= 134217

Seems to work okay and the audio remains synced so I guess I won't complain. Although if someone knows what that error means please let me know.

[svnpenn]

That error has existed for years. Sometimes FLV sends frames out of order and FFmpeg doesnt know how to deal with it.