Problems converting FLV

[am_dew]

I have some FLV files that I cannot get to convert to any other format without the audio getting way out of synch. My tool of choice for doing this is TMPGEnc Express 4.0 but I have tried several different methods and they all yield the same results.

To make a long story short, what I think might be the root of the problem is that when I play back the file, the time counter on the player (ie. Windows Media Player) is not true to real time. For example, I started the clip in Windows Media Player and at the same time started a stop watch. After 1 minute according to the Windows Media Player counter, the stopwatch said just 57 seconds. If I let it play longer, both times get further and further apart.

Another thing that is odd is that Windows Media Player reports the framerate of the source files to be 59 fps. And MediaInfo reports it to be 59.94. Here is MediaInfo's output for one of these FLV files:

General
Format : Flash Video
File size : 404 MiB
Duration : 1h 7mn
Overall bit rate : 840 Kbps
_framerate : 59.940
_width : 640.000
_height : 360.000
_videocodecid : avc1
_videodatarate : 750.000
_videokeyframe_frequency : 30.000
_audiocodecid : mp4a
_audiosamplerate : 44100.000
_audiochannels : 2.000
_audiodatarate : 128.000

Video
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.1
Format settings, CABAC : No
Format settings, ReFrames : 2 frames
Muxing mode : Container profile=Unknown@3.1
Duration : 1h 7mn
Width : 640 pixels
Height : 360 pixels
Display aspect ratio : 16:9
Frame rate mode : Variable
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Color primaries : BT.601-6 525, BT.1358 525, BT.1700 NTSC, SMPTE 170M
Transfer characteristics : BT.709-5, BT.1361
Matrix coefficients : BT.601-6 525, BT.1358 525, BT.1700 NTSC, SMPTE 170M

Audio
Format : AAC
Format/Info : Advanced Audio Codec
Format version : Version 4
Format profile : LC
Format settings, SBR : No
Duration : 1h 7mn
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Bit depth : 16 bits

Any help would be appreciated. I really would like to get these files to MPG-2 so I can convert to DVD. Thanks!

[Bonie81]

Try WinFF GUI (Option Menu ---> Additiona Option, and set desired parameters) or SGI Video Converter.

[am_dew]

Thanks but I think I've figured out what the problem is.

MediaInfo says the 'Frame Rate Mode' is "Variable". Every other video file I've worked with and been successful at converting is "Constant" for the 'Frame Rate Mode'. To my very unexperienced thinking when it comes to video files, this difference would mean that the video frame rate varies constantly and so if you separate the audio from the video, there is no way to keep them in synch with one another.

[poisondeathray]

You can extract the timecodes eg. flvextract, then mux them into a new container . The timecodes tell the player to speed up or slow down. Not all container formats support VFR. mkv and mp4 do. I'm not sure how to make a VFR DVD (mpeg2-ps)

You can try to make it CFR with avisynth e.g.

DirectShowSource("video.flv", fps=59.94, convertfps=true)

You still have to do some other maniplations because your framerate and resolution isn't DVD compliant . e.g. you might resize to 720x480 if you live in NTSC land , and you might interlace it if you want a 60i DVD. Otherwise you could select every 2nd frame for a 30p DVD

[am_dew]

Thanks. I used flvextract to extract. Can you point me to anything that explains how to mux them into a new container?

[poisondeathray]

Thanks. I used flvextract to extract. Can you point me to anything that explains how to mux them into a new container?

In case I wasn't clear above, this won't help you with making a DVD (as in DVD-video). You're just replacing a VFR FLV with a VFR MKV. Same problem.

If you wanted to make a VFR MKV , then you mux the timecodes in using mkvtoolnix. Highlight the video track, general track options tab, there is a box for timecodes

[am_dew]

Thanks very much, but in taking a quick look at these tools you kindly suggested, I think I'll just live with the fact that I can't make a DVD out of this FLV file.

[Bonie81]

Remuxing may cause video and audio out-sync problem, unless and until sync points indices map is created.

[am_dew]

Thanks to you both. It seems that the process of doing this is clearly not something just anyone can do with what I would call "consumer level" tools and knowledge, and as much as I'd like to try and figure it all out, I don't think it would be worth the time.