Transcoded x264 choppy on MVP

[JonRoyle]

can you post your transcode command line? It didnt seem to make any difference here. There are only two variables here surely: the version of ffmpeg and the parameters passed to it?

No Probs - this is what I now use:

<MVPFFmpegTranscodeCmdLinePAL>-y -i "{SOURCE_FILE}" -sameq -ac 2 -async 1 -ab 256k -r 25 -s 720x576 -f svcd "{DEST_FILE}"</MVPFFmpegTranscodeCmdLinePAL>

Jon

[zehd]

No Probs - this is what I now use:

<MVPFFmpegTranscodeCmdLinePAL>-y -i "{SOURCE_FILE}" -sameq -ac 2 -async 1 -ab 256k -r 25 -s 720x576 -f svcd "{DEST_FILE}"</MVPFFmpegTranscodeCmdLinePAL>

Jon

I have yet to play with this. I'm still having trouble with getting MKVs transcoding faster than real time, on my 2 Ghz machine. So far, it's the only file type (not to mention what's inside the file) that I'm having trouble)

Oh well I nailed TS (I think I did) so this is next...

[zehd]

No Probs - this is what I now use:

<MVPFFmpegTranscodeCmdLinePAL>-y -i "{SOURCE_FILE}" -sameq -ac 2 -async 1 -ab 256k -r 25 -s 720x576 -f svcd "{DEST_FILE}"</MVPFFmpegTranscodeCmdLinePAL>

Jon

I'm using the same ainmatrix file. It looks good played natively

I'm getting nothing but stuttering. I've never really had trouble with stuttering audio before but I get it!

I've tried several combinations,

using or removing the -sameq (as it is counter productive to make it the same quality AND in svcd format)

changing dimensions to something smaller (352x240NTSC usually helps out he transcoder)

trying both the default ffmpeg and ffmpeg-alt.exe, (that seems to be great on all my other trouble formats and files)

I suspect transcoding an mkv at all, let alone on the fly is relegated to super computers' domain...

[stu8080]

Nothing i try on that file seems to make any difference, but its not down to horsepower, i vary from x1.5 to x2 speed when transcoding with a dual core 3ghz athlon, not the fastest by any stretch these days.

Im going to have a play with 2 pass when i get chance and see if that makes any difference and perhaps have to d/l both high def and standard avi's from now on!

[HtV]

My 2 cts:
I wonder why that svcd parameter is there, or the other way round: why the resolution is there. They don't comply with each other. (is that good english?)
from wikipedia:

Video

• Codec: MPEG-2
  
• Resolution: 2/3 D1
  • NTSC: 480x480
    
  • PAL/SECAM: 480x576
    
  
  
• Aspect Ratio: 4:3 / 16:9
  
• Framerate:
  • NTSC: 29.97 frames per second
    
  • PAL/SECAM: 25 frames per second
    
  
  
• Bit rate: Up to 2,600 kilobits per second
  • Rate Control: Constant or variable bit rate
    
  
  

Unlike other CD-based formats, such as China Video Disc and Video CD, Super Video CD video is incompatible with the DVD-Video standard due to a conflict in resolution. However, SVCD resolution video is supported by the HD DVD standard.
Interlaced video is supported for SVCD video, though not required, except for any video at 23.976 frames per second which must use 3:2 pulldown.
The combined audio and video bit rates should not exceed 2756 kilobits. This data rate was chosen, in part, to ensure compatibility with slower and less expensive "2 × speed" CD drives

I don't know if it really interferes with each other but it probably doesn't help. I guess -videocodec mpeg2 and -acodec mp2 (or mp3) should do

Hans

[JonRoyle]

I don't profess to be an expery in ffmpeg and I arrived at my transcode settings by trial and error so accept that there could be some inconsistencies but if it works....

The use of the "-f svcd" was instead of typing "-acodec mp2 -vcodec mpeg2video" though the latter would be more accurate as the rest of my settings override the svcd standard.

The other settings were chosen to extract the best quality transcode that I could without stutter etc with the aim of using on MVP or elsewhere. I used the -sameq as I found that high quality did not appear to impact playability from a stutter/speed perspective but a low quality did impact visual appearance - so what the heck go for the highest.

I agree this is not an issue on machine horsepower, purely how effectively ffmpeg transcodes. When I play the resultant file from the transcode back via vlc it is watchable but not as smooth as playing the mkv directly with vlc

Would value the wisdom of someone who knows more about ffmpeg (NB the later versions are much better than the default one shipped with native GBPVR install)

Jon

[zehd]

I don't profess to be an expery in ffmpeg and I arrived at my transcode settings by trial and error so accept that there could be some inconsistencies but if it works....

The use of the "-f svcd" was instead of typing "-acodec mp2 -vcodec mpeg2video" though the latter would be more accurate as the rest of my settings override the svcd standard.

The other settings were chosen to extract the best quality transcode that I could without stutter etc with the aim of using on MVP or elsewhere. I used the -sameq as I found that high quality did not appear to impact playability from a stutter/speed perspective but a low quality did impact visual appearance - so what the heck go for the highest.

I agree this is not an issue on machine horsepower, purely how effectively ffmpeg transcodes. When I play the resultant file from the transcode back via vlc it is watchable but not as smooth as playing the mkv directly with vlc

Would value the wisdom of someone who knows more about ffmpeg (NB the later versions are much better than the default one shipped with native GBPVR install)

Jon

I have started to play with tsmuxer and mkv2vob. I was able to start a re-mux (not a transcode) and then start watching the show being muxed in progress...

My only problem is working with letterbox. I need to be able to pop a 2.35:1 into a 16:9 frame, or It's not worth watching...

[mvallevand]

Frank, It will be impossible to simply remux most mkv files into a format that the mvp can handle.

Martin

[zehd]

Frank, It will be impossible to simply remux most mkv files into a format that the mvp can handle.

Martin

I think I know why you say that. Because there can be so many formats in the mkv container, I might have just lucked out.

mkv2vob, gave me only two output options. MPG and m2ts. (I didn't see 'VOB' as the name would suggest but didn't look too hard.)

While processing, the program said that it wasn't transcoding but only remuxing.

The file was a MVP playable file, and I could start watching while the process was in progress...

Huh...


Edit: NEVERMIND

[pBS]

you are overriding all the other params when you put the -svcd last...
not to mention ffmpeg defaults to ntsc and you haven't specified -f pal-svcd so it's probably trying to make an ntsc svcd out of it!
put the -f pal-svcd at the beginning, just after the -i xxx so it sets all those presets, then the params you have after will override those before them.. the size,rate,etc..
just using "-y -i xxx -f pal-svcd output" sets all the format properties necessary for a pal-svcd...anything after that on the line will override...anything before gets overridden by pal-svcd..

so "-y -i xxxx -f pal-svcd -s 352x576 output.mpg" will correctly set framerate[25],framesize to 480x576, aspect 4:3, then the added -s 352x576 after it, changes the size...
if you want a smaller size [352x288] just specify -f pal-vcd and that's it..

-sameq is relative to size,same amount of comp. errors in each...i use -qscale 4 as it allows *some* compression while maintaining a constant quality without waste..
-sameq is same as -qscale 1

hope that makes more sense...:eek: