mp4 capture appears distorted. Fine in quicktime. Screenshots on post

[flamy]

Hi I'm capturing using a CHD-PVR1 to MP4 720x480, 29.970029 fps. Playback in Quicktime is absolutley fine. Playback in VLC (above screenshot) is however blocky and often quite distorted. Same when re-encoding using ffmpeg, or mencoder (super c).

Does this mean that the file is corrupt and cannot be re-encoded? If it plays fine in Quicktime, surely it can be converted.

[flamy]

I have attached the video file incase that helps finding a solution.

[poisondeathray]

It's interlaced h.264, and some decoders have problems with it

It decodes fine with recent ffdshow builds, or divx h.264 decoder

You can encode through avisynth (using ffmpegsource2 or qtinput or directshowsource with one of the decoders listeed above) + an encoder, for example. You might use a GUI, like xvid4psp for example. What format are you encoding to?

[flamy]

I'm going to MPEG2. I've installed the latest ffdshow build and given xvid4psp a try using both ffmpegsource and directshowsource. Yet I'm still getting the same results. Does the decoder automatically detect that the source is interlaced or do I need to set this somewhere?

[poisondeathray]

MPEG2 as in for DVD?

Did you use ffms or ffms2 ? ffms is the older version based on old library and has issues with interlaced AVC decoding. Directshowsource() + ffdshow will only work properly if your mp4 splitter setup properly. If you are on Win7 you need to use the codec filter setup tool to override MS defaults

https://www.videohelp.com/tools/Preferred_Filter_Tweaker

FFMS2 works for me, here was my script, and I used HCEnc (free MPEG2 encoder, much better quality than ffmpeg's MPEG2 encoder which xvid4psp uses). I recommend this because it's more consistent than using directshow for decoding , which uses system installed filters and codecs (for example , directshowsource works on my configuration but not yours, probably because you have it configured differently)

ffmpegsource2("WINT0003.MP4")

I set it to DVD compliant, interlaced , TFF

[flamy]

Brilliant! HCEnc+ffms2 worked perfectly, thank you.

Yes I was looking to convert to MPEG2 for DVD, so this does just the job.

I was initially using just ffms so that must have been the problem when using xvid4psp, however thanks for the tip this is a very good gui for ffmpeg I think it will come in handy.

It's a wonder why this piece of hardware I've bought encodes h.264 in such a way, I've never had such a problem before with h.264.

[poisondeathray]

I don't think the raw video stream is the issue, I think it's a playback issue with interlaced h.264 video in a .mp4 container for certain decoders and source filters (the observation that some players/decoders/splitters work fine supports this)

Here I demuxed the raw video stream with YAMB, then re-wrapped it with tsmuxer into a transport stream (so the video is unchanged, just "repackaged"), and VLC plays it fine. (I suspect the other tools would work with this version too)

[flamy]

ffmpegsource2("WINT0003.MP4", atrack=-1)

Using the above code I get a "no audio frames" error.

Would I have to first demux the mp4 and then specify the audio file seperatley?

[poisondeathray]

ffmpegsource2("WINT0003.MP4",atrack=-1)
info()

Open that script up in vdub or avsp, what does it say?

You shouldn't have to demux audio

It reports audio for me, 2 channels , so you could use that same script to feed into an audio encoder that accepts avs scripts (or use soundout() in avisynth)

What version of ffms2 are you using? I am using this one (2.13)
http://code.google.com/p/ffmpegsource/

Delete the index generated, and retry (if you indexed it before without audio at one point, it might give that error)

[flamy]

Version 2.13 of ffms2.

[poisondeathray]

it's reporting audio in the script

what software gives you the "no audio frames error"?

[flamy]

HCgui:

[poisondeathray]

HCenc doesn't encode audio.... it only encodes MPEG2 video elementary streams

As I mentioned earlier, you can use that script to feed into any audio encoder that accepts avs scripts (e.g megui, behappy), or use the soundout() plugin directly in avisynth

[flamy]

Have tried deleting the index although I'm getting the same error message.

[poisondeathray]

Don't pass through audio for HCenc (ie. don't use atrack=-1 ; or use ffvideosource() instead)

I'm using 0.24beta , you are using 0.23 HCenc , might explain some differences as well
https://www.videohelp.com/download/HC024_beta_16-02-2010.zip

[flamy]

I'm now using v0.24 beta and it's no longer showing that error message.

Could you show me an example script I would use? Do I need to process the audio seperatley and then re-wrap them after processing individually?

[poisondeathray]

The script is only for frameserving to and encoder video & audio (avisynth has no authoring capability - you need an authoring tool)

DVD Authoring is the process that multiplexes audio & video and creates the accessory files and structure required for DVD playback. Standard DVD players can't play everything; they have some special requirements

Have a look at some basic guides on this site for "what DVD is" and "DVD authoring".

https://www.videohelp.com/dvd
https://www.videohelp.com/author

Most people that author their own DVD's do audio , video, menus separately. They do this because they want control over everything, including quality, encoding settings, assets, etc...

There are easy to use packages like AVStoDVD , DVDFlick or paid easy to use ones like ConvertxtoDVD , but they might exhibit those decoding errors in your screenshot, since they might be using a different decoder. You have less control by using easy to use packages

Some free authoring tools would be GUI for DVD author, DVDAuthorGUI, or DVD Styler

[flamy]

OK, thanks for all the help. I've resolved the video encoding issue anyway, that was the main thing.