On2VP7

[tb582]

I've spent the past couple of days trying to get an MPEG-4 with AVC codec (FourCC: avc1) - file to On2vp7 WITH Vorbis audio. I now have a few questions.

I've heard that AVI container and Vorbis audio do not work well together, can anyone provide any links as to why this is?

Is the best codec to then use MKV?

I've tried using MediaCoder to encode MKV container with the VFW set to the vp7 codec but I keep getting cannot mux audio video once the transcode is done.

I have been able to successfully export an AVI out of VirtualDub with audio off as I cannot get OGG Vorbis audio withing virtualdub, even then I dont know if I want an AVI file.

So I guess this leads me to being stuck trying to use MediaCoder with MKV as the container Flash Video as the format and VFW - vp7.dll as the "Backend" VFW.... Right?

[poisondeathray]

I've heard that AVI container and Vorbis audio do not work well together, can anyone provide any links as to why this is?

AVI container uses outdated vfw system, and not all applications will be able to play back the vorbis audio correctly. An ugly hack is used to force it in, just like h.264 in avi.

Is the best codec to then use MKV?

MKV is a container, not a codec. It depends on what your goal is to determine what is "better" for your purposes

I've tried using MediaCoder to encode MKV container with the VFW set to the vp7 codec but I keep getting cannot mux audio video once the transcode is done.

The vorbis streams generated by vfw encoders are not complaint. Using a proper method to generate an ogg audio file will allow it to work with mkvmerge. For example, using MeGUI. If you use vdub, the vfw generated form of the ogg is not recognized and you will get errors

I have been able to successfully export an AVI out of VirtualDub with audio off as I cannot get OGG Vorbis audio withing virtualdub, even then I dont know if I want an AVI file.

You can generate OGG vorbis in avi, but it uses an ugly vfw hack. - the resulting stream is not compliant with many software eg. mkvmerge even if you wanted to swap containers won't recognize it as legitimate

So I guess this leads me to being stuck trying to use MediaCoder with MKV as the container Flash Video as the format and VFW - vp7.dll as the "Backend" VFW.... Right?

Depends on what your goals are and what you want to do with it or what you are using to play it. Not many people use VP7/vorbis combo, there are better alternatives.

[tb582]

Thanks for your great reply -

I guess then since I've already exported out just the audio to OGG Vorbis using MediaEncoder - I just need to get the video into MKV - hopefully MediaEncoder will do that now that it doesn't have to worry about the audio.

What is recommended app. to mux the ogg file with the mkv file that I hopefully will get out of MediaEncoder? (and I dont believe that this app. will transcode the video at all correct?

I did download MKVtoolnix and imported my AVI file from Vdub into it but it looked like it was going to change the video file.....

I guess overall I think it will be best to get the MKV file out of MediaEncoder which I'll have to try tomorrow, I still dont see any reason why MediaEncoder cannot mux the Vorbis audio with the MKV file...ugh.

[Midzuki]

I've spent the past couple of days trying to get an MPEG-4 with AVC codec (FourCC: avc1) - file to On2vp7 WITH Vorbis audio. I now have a few questions.

I've heard that AVI container and Vorbis audio do not work well together, can anyone provide any links as to why this is?

Vorbis Audio works in the so-called "Variable Samplerate" mode, and the VfW
interface was not designed to deal with that. In other words, if you try to seek
along the clip, you'll get instant loss of synchronization between video and audio.

AFAIK, there are only three "well-known" containers which support Vorbis audio
properly: MKV, OGG, and ASF Regarding OGG especifically, I don't recall whether
it supports VP7 though.

What is recommended app. to mux the ogg file with the mkv file that I hopefully will get out of MediaEncoder?

MKVmerge or AVI-Mux GUI.

\\\

[poisondeathray]

I don't use "mediaencoder", I assume that's part of mediacoder?

If you already have a vp7 in avi video (e.g from vdub), and a compliant .ogg audio file (not one generated from vfw system), mkvmerge (mkvtoolnix) will work to re-wrap both into an .mkv file. It 100% does not re-encode - it has no capacity to do such a thing

[tb582]

I don't use "mediaencoder", I assume that's part of mediacoder?

Ahh yes once again I have screwed up my acronyms, I did mean MediaCoder.

If you already have a vp7 in avi video (e.g from vdub), and a compliant .ogg audio file (not one generated from vfw system), mkvmerge (mkvtoolnix) will work to re-wrap both into an .mkv file. It 100% does not re-encode - it has no capacity to do such a thing

YES!! thats exactly what I have an AVI video with no audio in VP7 format from Virtualdub, plus the .oog audio file exported from MediaCoder - I'll definitely give MKVmerge a try tomorrow.

[tb582]

Just out of curiosity, is there no way to have the vp7 codec within an FLV or MPEG4 wrapper with OGG audio?

[Midzuki]

You could try that with ffmpeg, but the resulting file quite probably
will be unplayable to any other applications than ffplay.

[tb582]

You could try that with ffmpeg, but the resulting file quite probably
will be unplayable to any other applications than ffplay.

Yeah, I dont think I'm going to try it, I'll stick with the avi - MKV/OGG muxer. But I dont understand vp6 goes to flv so why wouldn't vp7, you think on2 would have some detailed documentation about all of this....

I mean so I guess in the end it doesn't really matter what container the vp7 encoded file is in, right? It could be in mp4/flv/mpeg etc??

[Midzuki]

http://en.wikipedia.org/wiki/Comparison_of_container_formats says:

MP4 supports:

Video formats:
MPEG-1, MPEG-2, H.263, MPEG-4 ASP, VC-1, MPEG-4 AVC

Audio formats:
MPEG-1 Layers I, II, III (MP3), MPEG-2/4 (HE)-AAC, AC-3,
Vorbis (with private objectTypeIndication), Apple Lossless.

http://en.wikipedia.org/wiki/Flv says:

Audio in Flash Video files is usually encoded as MP3. However, audio in Flash Video files recorded from the user's microphone use the proprietary Nellymoser codec. FLV files also support uncompressed audio or ADPCM format audio. Recent versions of Flash Player 9 support AAC (HE-AAC/AAC SBR, AAC Main Profile, and AAC-LC).

Codec support

* H.264
* VP6
* MPEG-4 ASP
* Sorenson H.263

[tb582]

If you already have a vp7 in avi video (e.g from vdub), and a compliant .ogg audio file (not one generated from vfw system), mkvmerge (mkvtoolnix) will work to re-wrap both into an .mkv file. It 100% does not re-encode - it has no capacity to do such a thing

YES!! thats exactly what I have an AVI video with no audio in VP7 format from Virtualdub, plus the .oog audio file exported from MediaCoder - I'll definitely give MKVmerge a try tomorrow.

I have my final mkv file but yet the bitrates are incorrect, I have my AVI from virtual dub which is not the exact CBR that it was specified in the On2 settings, then I have the muxed file which shows a lower video bitrate than the AVI.

[poisondeathray]

How are you determining the "video bitrate" ?

If you are using a program like mediainfo, it just reads the header info. If it makes you feel better you can use a hex editor and make it a "fake" 1000000000 kbps , or even 1 kbps. It does nothing to the actual video.

The precise way is the calculate it, subtracting the audio bitrate and container overhead . The avi container and .mkv container should be different by a few kb overhead (mkv is smaller) so that might be your discrepancy

bitrate = filesize/running time

If there is a big discrepancy in your filesize (not just a few kb), then there is a problem, and something probably went wrong with the muxing - in that case mkvmerge should have spit out an error message

[tb582]

How are you determining the "video bitrate" ?

If you are using a program like mediainfo, it just reads the header info. If it makes you feel better you can use a hex editor and make it a "fake" 1000000000 kbps , or even 1 kbps. It does nothing to the actual video.

The precise way is the calculate it, subtracting the audio bitrate and container overhead

bitrate = filesize/running time

If there is a big discrepancy in your filesize (not just a few kb), then there is a problem, and something probably went wrong with the muxing - in that case mkvmerge should have spit out an error message

Yes I'm using Mediainfo - the AVI file from Vdub is about 200k off from what I had specified in the on2 settings, and the mkv file is about 85k off from the AVI.

[poisondeathray]

If you examine with a hex editor, I am 100% sure the actual video portion of the video stream (not the junk header part) is the same in both containers.

If you use mkvextract, you will get back your original avi, but slightly smaller than the original avi, but mediainfo will read the bitrate as the same original avi (because it just reads header info, it doesn't analyze the video like a stream analyzer does)

[tb582]

If you examine with a hex editor, I am 100% sure the actual video portion of the video stream (not the junk header part) is the same in both containers.

If you use mkvextract, you will get back your original avi, but slightly smaller than the original avi, but mediainfo will read the bitrate as the same original avi (because it just reads header info, it doesn't analyze the video like a stream analyzer does)

Hmm thats encouraging, can you provide any links to a Hex editor or a stream analyzer?

[Midzuki]

http://www.thefreecountry.com/

[tb582]

http://www.thefreecountry.com/

not very helpful you might as well of sent me to google

[poisondeathray]

vdub has a built in hex editor (tools=>hex editor)

google lists a whole bunch too...not that hard to find

[tb582]

Yes but I can't open the mkv file in vdub can I? - can you provide any links for any mkv hex editors where I can see the true bitrate?

[poisondeathray]

The hex editor is a separate tool in vdub, you don't open the mkv with vdub, you open it with the hex editor

Hex editors don't look at the true bitrate, you find the true bitrate by calculating it yourself by the formula above. Hex editor in this scenario is used to examine the raw data: If you skip to the actual video section (ignore the junk and meta data) , and you will see they are bit for bit identical (either the original avi, the mkv, or the mkv extracted avi). 100% guarantee or your money back

[tb582]

ok I downloaded Neo Hex Editor - lol I have no idea what I'm looking at here, well yes I know is the binary data but I dont see anything that says bit rate is ... errr

[poisondeathray]

^As I said earlier, it's NOT to measure the bitrate; I suggested using a hex editor to confirm that the data was unaltered (i.e. no re-encoding upon container swapping).

If you want more proof, or want to measure the bitrate exactly, you need to extract the raw binary file.

You can use avi-muxgui (which supports avi and mkv), right click and use "extract binary". That raw file will not have any container. Guess what, the raw file will be identical for either the avi or mkv!

Now you can measure the EXACT bitrate (even without container overhead) by using that raw file and the formula above.

[tb582]

^As I said earlier, it's NOT to measure the bitrate; I suggested using a hex editor to confirm that the data was unaltered (i.e. no re-encoding upon container swapping).

If you want more proof, or want to measure the bitrate exactly, you need to extract the raw binary file.

You can use avi-muxgui (which supports avi and mkv), right click and use "extract binary". That raw file will not have any container. Guess what, the raw file will be identical for either the avi or mkv!

Now you can measure the EXACT bitrate (even without container overhead) by using that raw file and the formula above.

Ok I'll give that a try, is there a way to modify the displayed bitrate using avi-muxgui so that at least it shows up properly in Mediainfo?