Audio from movies with non-standard framerates.

[Maikeru-sama]

Hi forum, I just had some questions about audio and fps.

Question 1
My encoder of choice is CCE. The knowledgable folks on this forum taught me how to use CCE, AviSynth and DGPulldown to convert non-standard framerate video to NTSC compliant DVD files.

When I was taught this, I was still encoding both the audio and video in CCE. However, the same people here told me that I should always disable the audio in CCE, as it is a video encoder and let an audio program handle the audio. This was great advice because CCE rarely crashes now that I do that.

Say I have a video with these specs:
Video fps = 20.00

If I use CCE and Avisynth (script is at the end of this post) to convert the video to NTSC compliant, can I use a program like FFMPeg (my audio encoder of choice) or some other command line utility to convert the audio to the same frame rate?

Below is the script someone from here gave me a while back to use for non-standard fps:
<SCRIPT>
AVISource("C:\mymovie.avi")
LanczosResize(640,336,0,3,592,454)
AddBorders(40,72,40,72)
ChangeFPS(59.94)
SeparateFields()
SelectEvery(4, 0, 3)
Weave()
ConvertToYUY2()
</SCRIPT>

Question 2
I have an AVI file that is 59.94 fps. Would I still have to use the methods discussed above, or is 59.94 NTSC compliant. I know 59.94 is a special fps, I just don't know its actually meaning.

[redwudz]

Audio doesn't have a framerate, just length to determine it's playback time. Check the length of your converted video file and your audio file. If they match, then you just need a format for the audio. If they differ, you can stretch or compress the audio length with a audio editor like Audacity to change it. If the change isn't too much, you may not have to adjust the pitch, but Audacity can do that also.

Someone else may be able to give you help with your 59.94fps video. But what format is it in? What codec is it using?

[pcspeak]

Hi.

59.94/2 = 29.97.
Sure to be NTSC

Open it in http://mediainfo.sourceforge.net/en. Change to View/Text. Cut and past the text in a post.
Glad to have a look at it.

[Maikeru-sama]

Hi.

59.94/2 = 29.97.
Sure to be NTSC

Open it in http://mediainfo.sourceforge.net/en. Change to View/Text. Cut and past the text in a post.
Glad to have a look at it.

I decided to go ahead and encode the audio and video together in CCE and be done with it . However, I am going to post the information because I would really be in trouble if the files were MP4s as CCE has alot of trouble handling audio in that format:

<MEDIAINFO>
General #0
Complete name : C:\mymovie\myvideo.avi
Format : AVI
Format/Info : Audio Video Interleave
Format/Family : RIFF
File size : 215 MiB
PlayTime : 23mn 54s
Bit rate : 1257 Kbps
StreamSize : 4.03 MiB
Writing library : VirtualDub build 23350/release
Comment : CRC32�F03A683F3

Video #0
Codec : XviD
Codec/Family : MPEG-4V
Codec/Info : XviD project
Codec profile : Streaming Video Profile/Level 1
Codec settings, Packet bitst : Yes
Codec settings, BVOP : Yes
Codec settings, QPel : No
Codec settings, GMC : 3
Codec settings, Matrix : Default
PlayTime : 23mn 54s
Bit rate : 1041 Kbps
Width : 704 pixels
Height : 396 pixels
Display Aspect ratio : 16/9
Frame rate : 59.959 fps
Resolution : 8 bits
Chroma : 4:2:0
Interlacement : Progressive
Bits/(Pixel*Frame) : 0.062
StreamSize : 178 MiB

Audio #0
Codec : MPEG-1 Audio layer 3
PlayTime : 23mn 54s
Bit rate mode : CBR
Bit rate : 192 Kbps
Channel(s) : 2 channels
Sampling rate : 48 KHz
Resolution : 16 bits
Video0 delay : 24ms
StreamSize : 32.8 MiB
Writing library : Gogo (after 3.0)
</MEDIAINFO>

[jagabo]

The script you gave should work. You don't need the ChangeFPS() command since the video is already 59.94 fps.

Your 20 fps video could be encoded at 20 fps progressive MPEG2 and then have pulldown flags added with DGPulldown. That would give better quality.

None of what you are doing changes the running time of the video so there's no need to adjust the audio.

[manono]

Your 20 fps video could be encoded at 20 fps progressive MPEG2 and then have pulldown flags added with DGPulldown.

Right, except no encoder I know of will actually encode for 20fps. When I have silent films at 19.98fps, I encode for 23.976fps and then run the result through DGPulldown set for 19.98->29.97fps.

I also raise all my bitrates by a factor of 23.976/19.98=1.2 so the sizes and max/min bitrates come out correct. And, as you say, since the lengths remain the same no audio stretching has to be done.

[jagabo]

no encoder I know of will actually encode for 20fps

You're right. I keep forgetting that MPEG only allows certain frame rates. And 20 fps isn't one of them.

[Maikeru-sama]

The script you gave should work. You don't need the ChangeFPS() command since the video is already 59.94 fps.

Your 20 fps video could be encoded at 20 fps progressive MPEG2 and then have pulldown flags added with DGPulldown. That would give better quality.

None of what you are doing changes the running time of the video so there's no need to adjust the audio.

Jagabo, yes it does work and yes, I removed the ChangeFPS, but what I am trying to figure out is how I would accomplish the conversion if I wanted to encode the audio and video separately.

I personally do not like using CCE to encode the audio.

[guns1inger]

Load the avs script into virtualdub and save a WAV file

[Maikeru-sama]

Load the avs script into virtualdub and save a WAV file

Do you mean under "File save as" or go into the stream list? I am assuming I use "Direct Steam Copy"? Also, is there a way this can be done using a command line such as ffmpeg or mencoder?

[guns1inger]

In Virtualdub there is a Save WAV option under the File menu.

[jagabo]

If you Save WAV from VirtualDub in Audio -> Direct Stream Copy mode and your audio is compressed you will end up with a WAV file of compressed audio. A WAV file with MP3 compressed audio, for example. If you enable Audio -> Full Processing mode you will end up with uncompressed audio.

If you use VirtualDubMod you can demux the audio into its native container, MP2, MP3, AC3, etc. Streams -> Stream List -> Demux

[guns1inger]

This is audio from an avisynth script - would it not be uncompressed, as that is what avisynth serves by default ?

[jagabo]

This is audio from an avisynth script - would it not be uncompressed, as that is what avisynth serves by default ?

Sorry, I forgot he was using an AviSynth script. Yes, the audio would be uncompressed in that case because AviSynth will feed uncompressed audio to VirtualDub.

[Maikeru-sama]

Thanks fellas.

Also, is there a way I can do this using a command line utility?

[pcspeak]

With these installed. Or later versions.

BeSweetv1.5b31.zip
http://kurtnoise.free.fr/index.php?dir=BeLight/&file=bsn_20070513.zip -> bsn.dll copied into the BeSweet folder
aften-svn-r683-icl10_1-win32-bin.zip -> aften.exe copied into the BeSweet folder

All of the following will work. Code go on a single line. No wordwrap. Change path names to reflect your program locations. I save as Avcd.cmd, Amp3.cmd & Aac3.cmd. Reminds me that the command file only deals with the audio.

Extract audio from an AVI and output as mpg @ 44100. Used for creating a VCD.

"C:\VidAud\Besweet\BeSweet.exe" -core( -input "video.avi" -output "audio.mp3" ) -ota( ) -ssrc( --rate 44100 ) -toolame( -m s -b 128 )

Extract audio from an AVI and output as AC3

"C:\VidAud\Besweet\BeSweet.exe" -core( -input "video.avi" -output "audio.ac3" ) -ota( ) -ssrc( --rate 48000 ) -bsn( -exe aften.exe -b 224 )

Extract audio from an AVI and output as MP3.

"C:\VidAud\Besweet\BeSweet.exe" -core( -input "video.avi" -output "audio.mp3" ) -lame( -b 192 )

[Maikeru-sama]

With these installed. Or later versions.

BeSweetv1.5b31.zip
http://kurtnoise.free.fr/index.php?dir=BeLight/&file=bsn_20070513.zip -> bsn.dll copied into the BeSweet folder
aften-svn-r683-icl10_1-win32-bin.zip -> aften.exe copied into the BeSweet folder

All of the following will work. Code go on a single line. No wordwrap. Change path names to reflect your program locations. I save as Avcd.cmd, Amp3.cmd & Aac3.cmd. Reminds me that the command file only deals with the audio.

Extract audio from an AVI and output as mpg @ 44100. Used for creating a VCD.

"C:\VidAud\Besweet\BeSweet.exe" -core( -input "video.avi" -output "audio.mp3" ) -ota( ) -ssrc( --rate 44100 ) -toolame( -m s -b 128 )

Extract audio from an AVI and output as AC3

"C:\VidAud\Besweet\BeSweet.exe" -core( -input "video.avi" -output "audio.ac3" ) -ota( ) -ssrc( --rate 48000 ) -bsn( -exe aften.exe -b 224 )

Extract audio from an AVI and output as MP3.

"C:\VidAud\Besweet\BeSweet.exe" -core( -input "video.avi" -output "audio.mp3" ) -lame( -b 192 )

Thanks for the response. I will look into this.