Re: [ffmbc-discuss] Video with embedded silence audio track

[Lou]

On Tue, Jul 3, 2012 at 11:52 PM, esgratis <josec...@gmail.com> wrote:
> Hi,
> I would like to create a video with an embeded silence audio track with the
> same duration as the video file.
> The only input is the video file.

ffmbc -ar 48000 -ac 2 -f s16le -i /dev/zero -i INPUT -shortest -vcodec
copy -acodec ... OUTPUT

Alternatively if you also use ffmpeg you can use the aevalsrc audio source.

[n24.tec...@gmail.com]

-i /dev/zero   doesn´t work on Windows.

aevalsrc=0    is also not supported.
How can I create silent tracks on Windows?

regards,
Frank

[Eric Adler]

I believe I had this working. Here's the two command lines that I was
last using:

ffmbc -i D:\PATH\TO\FILE.mov -target xdcamhd422 -an
D:\PATH\TO\OUTPUT.mov -acodec pcm_s24le -ar 48000 -newaudio -acodec
pcm_s24le -ar 48000 -newaudio -map_audio_channel 0:1:0:0:1:0
-map_audio_channel 0:1:1:0:2:0

ffmbc.exe -i D:\PATH\TO\FILE.mov -threads 8 -target xdcamhd422 -an
D:\PATH\TO\OUTPUT.mxf -ac 2 -acodec pcm_s24le -ar 48000 -newaudio
-map_audio_channel 0:1:0:0:1:0 -map_audio_channel 0:1:1:0:1:1

I'm not sure exactly what each piece of this did anymore (I haven't
dug out my notes) or if these did indeed add the silent tracks
(perhaps it just grouped tracks), this is from a test that I later
ended up shelving due to other unrelated factors.

--
Eric

[n24.tec...@gmail.com]

My input file includes only one video track, but no audio.
So the filter mapaudiochannel does not work at this case.
But I have to create an XDCam with audio tracks or it would not be valid.

--
Frank

[marcl...@gmail.com]

In case help i still needed ... 

For windows use -i NUL 

Don't use -shortest because this "virtual" audio track has no length, you'll end up with a 1 frame long video track.That is why you won't have any statistics from ffmbc while encoding (eta for instance).

ffmbc -i "input.mxf" -ar 48000 -acodec pcm_s24le -f s24le -ac 1 -i NUL -pix_fmt yuv422p -r 25 -timecode 01:00:00:00 -target xdcamhd422 -tff  -y -an "output.mxf" -map 0:0 -acodec pcm_s24le -ar 48000 -newaudio -acodec pcm_s24le -ar 48000 -newaudio -map_audio_channel 1:0:0:0:1:0 -map_audio_channel 1:0:0:0:2:0