FLV joining possible?

[DarrellS]

I used Movica and all of the joined FLVs were out of sync.

Can convert each separate FLV to AVI with Virtualdub and FLV input plugin and join the AVIs with AviDemux (virtualdub will not join the AVIs since they have different sampling rate 24.00001 and 24.00000) and the files are in sync. Only problem is that I have to manually add each AVI one at a time. It will not append 10 AVI files automatically like Virtualdub does.

EDIT: Something else I notice with a lot of FLV files is that they have a blurred out section on the bottom that needs to be cropped out. If you notice in the images below, the top image from the FLV player looks fine but the image from Virtualdub ( or the finished AVI ) is messed up. By cropping off the blurred bottom of the clip in Virtualdub, the two images will be the same size.

[Placio74]

I used Movica and all of the joined FLVs were out of sync. ...

Movica not have restrictions for FLV.
However... of course, if You join FLV's with different FPS (or with VFR) - result is 'out of sync'.

... virtualdub will not join the AVIs since they have different sampling rate 24.00001 and 24.00000 ...

However... before You can use option - Convert to fps.

... Something else I notice with a lot of FLV files is that they have a blurred out section on the bottom that needs to be cropped out. If you notice in the images below, the top image from the FLV player looks fine but the image from Virtualdub ( or the finished AVI ) is messed up. By cropping off the blurred bottom of the clip in Virtualdub, the two images will be the same size. ...

http://forum.doom9.org/showthread.php?p=1125333#post1125333

[DarrellS]

However... before You can use option - Convert to fps.

It's my experience that you have to remove the audio to get the fps change to work or it just keeps making a 24.00001 clip which will not append to the 24.00000 clip. Any way you look at it, it's a lot of work. Been asking Avery for years to put in an option to ignore the .00001 difference and append the files anyway but he's not too keen on the idea. The creator of AviDemux could make life a lot easier if his append feature joined multiple AVIs. AviDemux has no problem joining files that are slightly different but it will only join two at a time.

[Placio74]

... AviDemux has no problem joining files that are slightly different but it will only join two at a time.

Odd...
I'm join 4 FLV's in Avidemux while ago...

[DarrellS]

I should have stated automatically. It's a PITA having to manually add 10 clips one at a time when you're working with multiple films. When Virtualdub works, it will add all sequential AVIs at once.

As for joining the FLVs with AviDemux, I have the same sync problems with these files as with Movica.

I have all the files converted and joined using the method I described earlier. It was just a lot more work than it needed to be. Only had one file that gave me sync issues and I used audio interleaving in Virtualdub to fix the problem.

[Jean]

It worked also. Avidemux is the ultimate toooooool.

I used Avidemux to join multiple flv and the output flv has serious sync problem. Is there better tool to join flv?

Thanks.

[Placio74]

... Is there better tool to join flv?

I'm afraid, rather not - especially when source vid'a have variable frame rate (which is typical for FLV).
Unless... maybe after change container or after transcoding.

[Jean]

... Is there better tool to join flv?

I'm afraid, rather not - especially when source vid'a have variable frame rate (which is typical for FLV).
Unless... maybe after change container or after transcoding.

Thank you.

I checked with avidemux that it is not variable frame rate. Would that make it better?

[Placio74]

...I checked with avidemux that it is not variable frame rate.

What 'say' MediaInfo about FPS?
And FLV Extract show exactly same True Frame Rate and Avg Frame Rate?

FLV must be as output 'format'?

Maybe any FLV sample files?

[Jean]

...I checked with avidemux that it is not variable frame rate.

What 'say' MediaInfo about FPS?
And FLV Extract show exactly same True Frame Rate and Avg Frame Rate?

FLV must be as output 'format'?

Maybe any FLV sample files?

Attached is the property.

[Placio74]

15.002 FPS - it does not look good.

Waht's info from other apps (especially from FLV Extract)?
And what's other files FPS?

Look at this:

[Jean]

[quote="Placio74"]15.002 FPS - it does not look good.

Waht's info from other apps (especially from FLV Extract)?
And what's other files FPS?

[Placio74]

This appears to be another issue...

Some wrong with reading total video duration... and then 'wrong' calculating FPS...

6390 frames / 425,943 sec = 15,002 FPS


BTW
If You demux video to AVI used FLV Extract and open in Avidemux, I guess then show more accurately total video duration (~426 sec) and then calculate 15,000 FPS.


Unfortunately, I not see easy way and without issues to join FLV's.

---

I'm not sure how it will A/V sync, but maybe try MEncoder...?

mencoder -forceidx -of lavf -oac copy -ovc copy -o output.flv clip1.flv clip2.flv clip3.flv

[Jean]

Thank you.

I tried to convert it using mencoder or Super. It is ok for a short video (a few min). It has a/v sync problem for a longer video.

Thought that it might be easy just join multiple flv. It seems no solution.

Thanks again for your help.

[katipo]

Old topic, but I remember visiting here last year when I was looking for the same thing. I never found a perfect solution so wrote my own program instead. Hope it helps someone out.

Andy's FLV Joiner
http://ferretsoft.active.ws

What is it?
A simple Flash Video file joiner program.
Great for joining multi part video clips that you've downloaded. e.g. YouTube

What's so special about it?
- tiny and fast
- no recoding of the file
- no quality loss
- able to handle VBR files without audio sync problems
- free!

[Baldrick]

Old topic, but I remember visiting here last year when I was looking for the same thing. I never found a perfect solution so wrote my own program instead. Hope it helps someone out.

Andy's FLV Joiner
http://ferretsoft.active.ws

What is it?
A simple Flash Video file joiner program.
Great for joining multi part video clips that you've downloaded. e.g. YouTube

What's so special about it?
- tiny and fast
- no recoding of the file
- no quality loss
- able to handle VBR files without audio sync problems
- free!

It worked fine on standard flvs. Adding it it to our tools list, Andys FLV Joiner. Have you tried it with flvs with h264 video?

[katipo]

It worked fine on standard flvs. Adding it it to our tools list, Andys FLV Join. Have you tried it with flvs with h264 video?

Hi, yes I've tested it with FLV1, VP6F and H264 formats.

The only caveat would be to make sure the clips use the same format.

[Baldrick]

The only caveat would be to make sure the clips use the same format.

Yep, but if you don't want to reconvert it's a requirement for most video format/containers.

[katipo]

Version 0.2 of my FLV Joiner is now available. http://ferretsoft.active.ws

Changes:
Now removes all Meta tags (not just the first) from the start of each appended file (compatibility)
Tweaked Interface: timecode info, browse button, single progress bar
Speed and memory optimizations

Sorry if this is the wrong place for posting this, but I couldn't find how to update the details on the Tools page.

[sldvd]

I have joined quite a few flv files with considerable success combining the use of 2 command line utilities - flvmerge.exe and flvtools.exe. Although flvmerge alone will enable you to join flv files, it however does not check the integrity of the flv files to be joined. So, if any of the flv files has a flaw, the resultant merged file will likely not be able to play to its end. Another notable setback of flvmerge is its inability to readjust the timecode to the combined length of the video. To overcome these shortfalls, you will have to use flvtool2 which not only allows you to check file integrity but also corrects the timecode problem that is generated by flvmerge.

The entire procedure I use to combine flv files is as follows. It is a bit cumbersome but does produce very good results:

• 1. First, copy and paste flvmerge.exe and flvtool2.exe into the folder containing flv files to be joined.
  2. Enter Windows Command Line interpreter, ie Run followed by cmd and Enter.
  3. Change directory (CD) to the flv folder.
  4. Use flvtool2 to check integrity of flv files to be joined: Flvtool2 -D video1.flv. Repeat this for remaining flv files.
  5. Now join the flv files using Flvmerge: flvmerge video1.flv video2.flv .... videon.flv. The output video is named merge.flv by default.
  6. Readjust timecode of combined video: flvtool2 -U merge.flv

That's it.
Hope this helps.

I just tried FLVMerge to merge some FLV files. VLC doesn't play the merged video correctly when I load it - it thinks the merged video is 15 minutes long when it should be 45 minutes long. The first video that was merged is 15 minutes long, and that's what VLC is showing - only the first video. FFmpeg also cannot make a lossless copy of the merged video - it fails at the first join point:

ffmpeg -i merge.flv -acodec copy -vcodec copy test.flv
.....
frame= 3707 fps=  0 q=-1.0 size=   16185kB time=123.55 bitrate=1073.1kbits/s
frame= 3745 fps=2084 q=-1.0 size=   16378kB time=124.83 bitrate=1074.8kbits/s
frame= 6734 fps=2932 q=-1.0 size=   26983kB time=224.47 bitrate= 984.7kbits/s
frame=10045 fps=3592 q=-1.0 size=   40164kB time=334.83 bitrate= 982.7kbits/s
frame=12648 fps=3836 q=-1.0 size=   52613kB time=421.60 bitrate=1022.3kbits/s
frame=15215 fps=4007 q=-1.0 size=   64341kB time=507.17 bitrate=1039.3kbits/s
frame=17072 fps=3973 q=-1.0 size=   72477kB time=569.08 bitrate=1043.3kbits/s
frame=19516 fps=4068 q=-1.0 size=   83454kB time=650.55 bitrate=1050.9kbits/s
frame=22327 fps=4215 q=-1.0 size=   96649kB time=744.23 bitrate=1063.8kbits/s
frame=25647 fps=4424 q=-1.0 size=  113663kB time=854.89 bitrate=1089.2kbits/s
[flv @ 01ca0050]st:0 error, non monotone timestamps 899716 >= 899716
av_interleaved_write_frame(): Operation not permitted

So it looks like FLVMerge does indeed have a timecode problem. So I tried both of the flvtool2.exe commands that you mentioned (one with the -D option on each individual file, and another with the -U option on the merged file), and all of the commands fail with the exact same errors:

ERROR: EOFError
ERROR: flv/amf_string_buffer.rb:37:in `read'
ERROR: flv/video_tag.rb:80:in `read_header'
ERROR: flv/video_tag.rb:47:in `after_initialize'
ERROR: flv/tag.rb:56:in `initialize'
ERROR: flv/stream.rb:449:in `new'
ERROR: flv/stream.rb:449:in `read_tags'
ERROR: flv/stream.rb:58:in `initialize'
ERROR: flvtool2/base.rb:272:in `new'
ERROR: flvtool2/base.rb:272:in `open_stream'
ERROR: flvtool2/base.rb:238:in `process_files'
ERROR: flvtool2/base.rb:225:in `each'
ERROR: flvtool2/base.rb:225:in `process_files'
ERROR: flvtool2/base.rb:44:in `execute!'
ERROR: flvtool2.rb:168:in `execute!'
ERROR: flvtool2.rb:228

None of the flv files were modified by flvtool2.exe. Looks like flvtool2.exe can't run on my Windows machine for some reason.