Transcoded x264 choppy on MVP

[zehd]

I have tried about half a dozen different versions, recent unofficial win32 builds, 12665 through to the latest i could find - 15815. None give me any sound, and when trying on command line i get errors about the audio bitrate being set too low (with 15815), it seems to set audio bitrate at 0kb/s and no sound on the resultant mpeg.

There is a log file created but its always empty - next best thing is a screengrab:

Yeah, I won't be using ffmepg. I'll be either using VLC or MEncoder

[mvallevand]

All three are pretty much equivalent since they used the same encoding and decoding libraries. ffmpeg is probably the most powerful, you just have to know the settings.

Martin

[JonRoyle]

Stu,

I have numerous mkv files which i play succesfully on MVP. This is my transcode setting
<MVPFFmpegTranscodeCmdLinePAL>-y -i "{SOURCE_FILE}" -sameq -ac 2 -ab 256k -r 25 -s 720x576 -f svcd "{DEST_FILE}"</MVPFFmpegTranscodeCmdLinePAL>

I also using an Apr08 ffmpeg binary.


Jon

[mvallevand]

JonRoyle there isn't a question of mkv transcoding, the question is near dvd quality available on the fly. The example stu8080 provided is close to what I saw a year or so ago, sometimes quality is better and sometime the judder is worse since mkv contents are extremely variable. You certainly have one wrong value -sameq

The real solution is to either to a nice 2 pass resampling conversion overnight or download both the avi and mvk.

Martin

[HtV]

Just curious: why is "-sameq" wrong?

Hans

[mvallevand]

It is used to keep the quality of the output the same, great for xvid dvd but it is not what you want when you must cut the quality so much.

Martin

[JonRoyle]

I tried lots of settings to maintain quality in transcoding whilst giving a smooth playback on MVP. It seems to work on my expanded collection of mkv files so I have kept it.

[pBS]

yea, the audio issue is because you have specified 192 not 192k or 192000
[new ffmpeg semantics]
that'll mess things up considerably..
might also wanna try -vsync or -async as it looks like the mkv you have has errors or non-standard frames that are tripping up ffmpeg but not players..

i know i had to give it a high muxrate and specify a larger buffer on mine to eliminate encode warnings...may help..
tho i notice you're doing some bad things, not specifying a video codec is making it come out mpeg1!!! problem right there..
tho i know 1 is faster, i'd try mpeg2..

and the -f pal-svcd is nice cuz it sets lots of params which should be almost perfect for this, and put a -s 352x288 after it to just change framesize..
[-f svcd sets it to 480x480 which is still fast and looks more like dvd, plus interlaced frames [smoother]]
try:

ffmpeg -y -i file.mkv -f pal-svcd -b 2400k -ac 2 -ab 128 -s 352x288 DEST_FILE.mpg >>transcode.log

or for faster, use -f pal-vcd [mpeg1,352x288,mp2 audio]

[stu8080]

Martin - im lucky quality and its effect on speed isnt an issue, as it transcodes near doubletime even on the highest settings, although theres little point in me increasing the quality past what the MVP can display - 352x288 interlaced mpeg2 with 192k mp2 stereo audio - is this right?

Jon - Did make some video lkook better, especially some of the terminator vids, but the Animatrix - the worst of the bunch and very noticable with its falling matrix text effect on the intro still jutters every second.

pBS - Audio working with the latest ffmpeg, was obvious from the logs! doh!
Does the instruction in </FFMPEGTranscodeCmdLinePAL.... create an mpeg2 file, as the file type is not specified? Or is this fed in as an output parameter?

Does the order of the parameters matter? ie -re must be before the input file, what about -async? anywhere?

[stu8080]

Can anyone explain the following parameters in a little more detail:

-qscale
-vsync - specifically the parameters required
-async - as above, but would i use one or the other, or both and for what reason? Does this sync the input to the output, or audio to video (or vice versa)
-map_meta_data outfile:infile - some relation to the two above commands?

A few other questions!
-I have a progressive input, if i leave the file deinterlaced, will my tv interlace the stream, or will the MVP? Will it cause issues and can i affect this?
-Frame rate is 60 fps in x264, my tv is 25 fps. I have heard of pulldown/reverse telecine and use it in ffdshow - how is this handled in ffmpeg. - My judder seems to relate to this, a slight freexe twice a second.