Encoding cuts of first 0.5-1.5 seconds

[Peer]

I have even more information for you.
I am a computer programmer and I could not sit still anymore, so I started looking at mencoder.exe to see if it's the link in the chain that's causing the trouble I have.
I noticed that CloneDVDmobile passes the video and audio data to mencoder through the stanrard-in (stdin). So I created a VOB file using the VOB passthgourh method, end I've encoded it with mencoder to MPEG4, and I was glad to see that it was encoded correctly without cutting off anything at the beginning.
So I think the developers in your team should look at the data they pass to mencoder via the stdin, because they're truncating something at the beginning.

Well, thanks for testing that. But, nope, CloneDVD mobile doesn't truncate anything.
Actually when you generate a VOB (passthrough) file, CloneDVD mobile simply sends the exact same data it would pipe into mencoder into a file. That's the only difference. So when you're looking at the VOB file, you see precisely the same data that mencoder receives.

So it's a bug in the way mencoder handles input from stdin. My guess is that you'll get the same result if you stream the VOB file into mencoder from the cmdline.

I'm aware of this "problem" - honestly, I find it difficult to see it as such, after all it is hard to find source material, where cutting off the first second results in anything more than 2 seconds of blackness instead of 3. And even in the other cases, like when I'm transcoding a specific chapter, I'd hardly call it a show stopper to miss a second from the beginning.

Nevertheless, I'll keep trying, but it is extremely hard to induce changes in mencoder. The developers have their own priorities.

 

[gianluca]

Hi Peer. Thank you for your reply!
I tried encoding the VOB with mencoder from the command line using the same parameters that CloneDVDmobile uses, and I that produced a file with no truncation.
Here it is: http://www.gianluca.net/mtm_cmdline.mp4
And here's the one with the first frames truncated: http://www.gianluca.net/mtm.mp4
I'm not saying that this proves anything, but I had done this test before you posted your message on this forum and I wanted to let you know.

I also want to let you know about one more test I did: I ripped and encoded that same chapter using mencoder. As you probably know mencoder can read straight from the DVD drive, so I selected that the drive/title/chapter and the encoded it with the same parameters from the command line, and the output MPEG4 was correct. Nothing was truncated. It’s interesting to see that mencoder does not truncate when reading directly from the source and encode to the same type of destination. Of course I understand that this does not pass data through stdin, but it’s interesting nonetheless.

I know I should not be telling you what do to, but as a fellow programmer I feel compelled to say that I would be willing to invest and order the DVD that causes this ("The Mary Tyler Moore Show" Season 4 – NTSC ) and run a tests with it. This is just my opinion.
The DVD is $14.99 USD + taxes and shipping on Amazon.com:
http://www.amazon.com/Mary-Tyler-Mo...000EXDS02/ref=pd_bbs_sr_2/103-3818649-1732615

I know this is a minor problem to you, but it’s not minor to me. I ask you to respect my opinion regarding this point. If you then decide not to fix this because of time/resources reason, then it’s a different story and I’ll look somewhere else for the solution to my problem. Id rather be told you don’t have time than hear you say you don’t think my problem is important enough.

Thank you in advance for all the time and work you’re willing to spend on this.

-Gianluca.

 

[Peer]

Hi Peer. Thank you for your reply!
I tried encoding the VOB with mencoder from the command line using the same parameters that CloneDVDmobile uses, and I that produced a file with no truncation.
Here it is: http://www.gianluca.net/mtm_cmdline.mp4
And here's the one with the first frames truncated: http://www.gianluca.net/mtm.mp4
I'm not saying that this proves anything, but I had done this test before you posted your message on this forum and I wanted to let you know.

No proving required. I know that I can reproduce this effect with a variety of discs. But it is clearly a problem with mencoder and I have very limited possibilities to go ahead and solve it - I will file a report to the mencoder development team.
You can stream the VOB file into mencoder using the pipe symbol and using '-' (dash) as input file. This should simulate what CloneDVD mobile is doing.
Then, I'm pretty sure, you'll get the same missing second - without CloneDVD mobile involved. I didn't yet have the time to try this myself but I will as soon as I hit the office again and find the time...

I know this is a minor problem to you, but it’s not minor to me. I ask you to respect my opinion regarding this point. If you then decide not to fix this because of time/resources reason, then it’s a different story and I’ll look somewhere else for the solution to my problem. Id rather be told you don’t have time than hear you say you don’t think my problem is important enough.

I'm one of those unfortunate people who grew up with only two eyes and two hands (please don't pity me, I've learned to deal with it ).
But seriously: I understand it may sound harsh if I tell you that I consider that problem a - very - minor one (in terms of collective pain it causes to our overall customer base). But I have a huge list of problems to solve and I need to prioritize.
So mencoder cutting off a second is certainly not a top priority, but rest assured, it is on the list. You're just unlucky, that it most certainly (I'm leaving some room for doubt here) is a bug in mencoder.

 

[Peer]

piping into mencode

Ok, just for the record:

type xy.vob | mencoder - -oac mp3lame -ovc xvid -xvidencopts bitrate=1000 
-o xy.avi

shows the same result. So it's really mencoder.