Need converter that lets me chop second off start of file.

[Jon.G]

Ok, so I'm getting ready for a trip, and have this really bad crappy tablet that I bought strictly for playing back video, since it was an advertised feature of this piece of junk.

I've found that this tablet has a major flaw, in that, if the video starts with a black screen, it won't playback the video on the file.

I have a bunch of files that many of them start with a black frame.

So, I've been converting them to mp4 using handbrake, it's convenient to be able to cue up a bunch of files, walk away and have it do it's thing, come back and they're all done. So I'd like to keep doing it with handbrake, or use another program that allows that same feature. The thing is....I need a program that I can just set to chop a second off the start of the file, so I can make sure my files all start with something other than a black frame, so they will all work on this piece of junk.

What will do this?

[yoda313]

I don't know about batch converting but something like avidemux can do it. Or virtualdub with the directshowsource filter to open any video file type.

However the only way I know to do it would be to manually do it for each video. That is open the video, select the range you want to save then do copy video, copy audio and save it as a new file.

Others here might be able to suggest a better way to instruct a converting program to do a range before you encode. I don't know off the top off my head how to do that.

Though You could do that in virtualdub. Use a x264 encoder (I'm assuming you are converting to h264 in the mp4 container, mp4 is a container not a codec). You could select the first and last frame of the video you want to convert then load a batch job and start it.

It would take a little trial and error to do it just right. But it should do it just fine, at least in theory I think.

[poisondeathray]

Tencoder is another option; it's a GUI for ffmpeg / mencoder and has a cut range , allows queue processing

[Jon.G]

tencoder is looking cool, I'll give that a go.

[Jon.G]

Yes, this is working great. The only downside is I have to tell it to cut the first second off of each individual file instead of just setting it to cut 2 seconds off of all files. But the up side is that once I have everything set, I can let it do it's thing and come back later when it's all done.

[poisondeathray]

If all the input files are the same file type (e.g. mp4), you can do it with a ffmpeg batch file (just double click instead of queuing each one up individually) . But it gets more tricky if you have different source file types

[poisondeathray]

Yes, this is working great. The only downside is I have to tell it to cut the first second off of each individual file instead of just setting it to cut 2 seconds off of all files. But the up side is that once I have everything set, I can let it do it's thing and come back later when it's all done.

Also, did you only want to cut them? Or re-encode them ?

If they were already in a compatible format for the tablet, and you only wanted to cut a few seconds off the start, it would be better to stream copy (no quality loss, much faster to process)

[Jon.G]

I was looking to cut and re-encode, but thanks.

[poisondeathray]

Lets say you had a folder of MP4 files that you wanted to re-encode to h.264/aac/MP4 and cut 2 seconds of the beginning

You can use ffmpeg's -ss for start time (in hh:mms.ms notation) . So for start at 2 seconds, it would be -s 00:00:02

1) Place a copy of ffmpeg.exe in the folder to be converted

2) Open a text file in notepad , copy & paste the following, save it, rename the extension from .txt to .bat

for %%a in ("*.mp4") do ffmpeg -i "%%a" -vcodec libx264 -crf 18 -acodec libvo_aacenc -b:a 128k -ss 00:00:02 "%%~na.new.mp4"

pause

3) double click the .bat file


If you wanted to change the encoding settings, audio settings eg. bitrate etc... just modify the batch file . I just randomly picked crf 18 and 128k for audio bitrate

There probably is a way to do it with multiple file types as inputs, but it's beyond my very basic knowledge of dos batch scripting