Is it better to split a file before or after encoding?

[twosocks]

I've been trying to make a SVCD from a .mov file. I'm able to encode it with MMT or ffmpegx, with no problems. The file size after encoding is about 1.7GB. I can split the file into 3 chunks with ffmpegx or mpegtxwrap but cannot complete the process of making burnable image or bin files without errors. I then tried Gumby, with partial success. It split the files and I was able to make burnable bin/cue files, however, when played on the DVD player (Norcent 201) the picture will jump about every second. It's like watching the second hand on a watch.

I've discovered, through trial & error that my Norcent will play VCD's and SVCD's but not XVCD's or XSVCD's. I've made VCD's, with success, but have not been able, so far, to make a playable SVCD. The SVCD's that do play on my machine are ones that have been sent to me from friends or family.

The file, in question, was encoded at 2500BR, 23.98fps, ltrbx.

I've been able to produce quality SVCD files with smaller (2 minute) "Test" files.

Is it better to split the .mov file in QT, first, before encoding and authoring?

[galactica]

The file, in question, was encoded at 2500BR, 23.98fps, ltrbx.

I've been able to produce quality SVCD files with smaller (2 minute) "Test" files.

Is it better to split the .mov file in QT, first, before encoding and authoring?

If the frame rate changes though out the movie, then yes, splitting it into chunks before you encode will help that.

Its intersting you can make "test" SVCD's that work fine, but when you use the same settings on the whole movie it doesnt work? Is that what your saying?

[twosocks]

If the frame rate changes though out the movie, then yes, splitting it into chunks before you encode will help that.

Is the jitter, every second, being caused by splitting after the encode?

Its intersting you can make "test" SVCD's that work fine, but when you use the same settings on the whole movie it doesnt work? Is that what your saying?

Yes, I made a small "test" file to see what the different Bit Rates looked like. As I mentioned, I'm able to make & play VCD's at 1152 and play SVCD's (the one's that we're given to me) at 2500. When I try something other like 2000 or 3000 BR, I get the same jitter, every second. This lead me to belive that my player would not be able to handle XVCD's or XSVCD's. So, this weekend, I proceeeded to encode/author the whole file, splitting it after the encode and burning with MMB. Then, disappointment, when the finished movie has the jitters.

Thank for your response, I've learned much from reading your posts and visiting your web page.

[galactica]

Is the jitter, every second, being caused by splitting after the encode?

It could be. But you would only see that when you hit the split point. how many times did you split and rejoin the files???

Yes, I made a small "test" file to see what the different Bit Rates looked like. As I mentioned, I'm able to make & play VCD's at 1152 and play SVCD's (the one's that we're given to me) at 2500. When I try something other like 2000 or 3000 BR, I get the same jitter, every second. This lead me to belive that my player would not be able to handle XVCD's or XSVCD's. So, this weekend, I proceeeded to encode/author the whole file, splitting it after the encode and burning with MMB. Then, disappointment, when the finished movie has the jitters.

Thank for your response, I've learned much from reading your posts and visiting your web page.

Well if you are going way above the SVCD k/sec of your player it will jitter like you say. SVCD is 2500k/sec standard.

Try somethign lower. Like 2000k/sec or even 1800k/sec and see what htey look like

suggest using CD-RW for this purpose.

by the way for quotes, you dont put [/quote] in the front of what you are quoting. You just do [quote]

[ZeroSix]

one of the problems you will encounter when splitting the MPEG file is that the headers often become corrupt. A solution to this is to run the resulting split mpeg files through VCDGear. This has worked for me on numerous occassions. Or you can demux and remux the split MPEGs. This has often worked as well.

The other and most sensible option is to split the file BEFORE encoding. That way you can be assured that each segment will have a genuine mpeg header the FIRST time, and it is a LOT easier to split a .avi or .mov file in quicktime than it is to split using mpegs using Mpgtxwrap.

You can even save the quicktime files with dependancies [not make them self-contained] as this will spare you hard drive space and it only takes a few seconds to copy and paste the desired segments in the QT Player.

If you are concerned about resulting MPEG size when using this method, I strongly recommend using standard SVCD / VCD / DVD bitrates and following the timecode rule.

VCD ? 74 - 80 minutes of video per disc depending on the media
SVCD ? 45 minutes of video per disc depending on the media.

By following these methods you will have eliminated the problems you are having with the stuttering and you will have generated standards-compliant SVCDs [or VCDs].

[twosocks]

It could be. But you would only see that when you hit the split point. how many times did you split and rejoin the files???

The large file (96 min.) was split into 3 chunks. I didn't rejoin them

Well if you are going way above the SVCD k/sec of your player it will jitter like you say. SVCD is 2500k/sec standard.

Try somethign lower. Like 2000k/sec or even 1800k/sec and see what htey look like

If memory serves me correctly, in the past, when I tried lower bit rates it created the jitter feature that I have discribed. Correct me if I'm wrong (I mainly use MMT to encode) but when I choose a non-standard bit rate, say, 2100, I've always checked the XVCD/XSVCD box. With the results that I've gotten, so far, this is what lead me to believe that the Norcent would not play anything but standard bit rates (1152 & 2500)

[twosocks]

The other and most sensible option is to split the file BEFORE encoding. That way you can be assured that each segment will have a genuine mpeg header the FIRST time, and it is a LOT easier to split a .avi or .mov file in quicktime than it is to split using mpegs using Mpgtxwrap.

You can even save the quicktime files with dependancies [not make them self-contained] as this will spare you hard drive space and it only takes a few seconds to copy and paste the desired segments in the QT Player.

I'm dividing up the QT file, as I type this.

If you are concerned about resulting MPEG size when using this method, I strongly recommend using standard SVCD / VCD / DVD bitrates and following the timecode rule.

VCD ? 74 - 80 minutes of video per disc depending on the media
SVCD ? 45 minutes of video per disc depending on the media.

The Mpeg size is not really a concern, I'd rather have a quality picture but I don't think that I'll be able to 45min, if I encode at 2500.

I'll post my results, when ready. Although it sounds like you already know how it will turn out.

Thank you

[twosocks]

I split the QT file (90 min.) into three equal (30 min) files. I used ffmpegX to encode at a bit rate of 1996, based on the ffmpegX calculator. I took the resulting mpeg and used MMB to create the cue/bin and burn the SVCD. I've only converted 1 of the 3 files, so far.



The resulting picture turned out great, when played on my Norcent but there were a number of places throughout the disc (more often towards the end of the file) where the picture and sound would stop for second or less and when the picture would start again it would be in slow motion for about 2 seconds.

As far as media, while going through these trials & errors, I used CDRW's but they have been older ones, that I had around a couple of years. Would this be part of the problem?

I can play the mpg file on my Mac with QT and it does not duplicate the problem.

I'm beginning to conclude that my Norcent may be great for DVD's but not for SVCD's.

I may need to try these on another player to see if I get the same results. At least I would know then if it is my Norcent or my SVCD creation procedures.

Agreed??

[ZeroSix]

the media usually has everything to do with playback on a set top player. Try playing the disc in your computer [not the mpeg file alone] using a program like VLC and see if the problem duplicates.

I dont know anything about your brand of DVD player, so i cannot say if it is a good choice for SVCD playback. If i were to make a suggestion it would either be a cheapo Apex or our house brand Divx player.

[twosocks]

the media usually has everything to do with playback on a set top player. Try playing the disc in your computer [not the mpeg file alone] using a program like VLC and see if the problem duplicates.

Unless it's just a fluke, I used a brand new CDRW and the disc played perfectly. New media must have everything to do with playback.

If i were to make a suggestion it would either be a cheapo Apex or our house brand Divx player.

House brand Divx player???????