[Kdenlive-devel] Kdenlive anamorphic problem in rendering to H.264 + sound issues

[Dan Dennedy]

On Fri, Dec 26, 2008 at 11:25 PM, Jean-Michel Pouré <jm at poure.com> wrote:
> Dear Friends,
>
> I made some changes to export profiles using
> http://itbroadcastanddigitalcinema.com/ffmpeg_howto.html
>
> There are still some problem:
>
> 1) H.264 rendering
> Download and HDV movie from our footage page
> http://www.kdenlive.org/contribution-manual/footage
>
> Then export to H.264. It is 4:3 and not 16:9

Looks fine in ffplay and vlc, but not inigo/kdenlive. I'll look into this.

> 2) Lossless/HQ profiles
>
> Rendering to Mpeg2 and H.264 I-frames only works very well.
> But I would prefer pcm_s16le audio codec. This is not possible, breaking
> export. Is it because Mpeg2 and H.264 should never have uncompressed
> sound? I am surprised. Any solution for uncompressed sound?

"linear pcm" should be possible, but I have little experience with it.
I will visit this after the next release. Please open an issue for it.

> 3) Number of channels
> Sometimes sources with several audio channels do not export well.

Please be specific about which render options.

> Example: http://www.poure.com/footage/sony-hdr-cx-6-1080i.mts
> which has two pcm_s16le audio channels.

I only see one 6-ch audio stream in that sample. I am not sure if you
are referring to multi-channel (more than stereo) or multiple audio
streams. Right now, MLT only deals with one audio stream.

> So it might be usefull to add ac=2 to some export profiles. What is your
> opinion?

Some audio formats do not like >2 channels. Right now, the resampler
which gets applied automatically to all producers should already
convert 6 channels to stereo. Full multi-channel support needs some
work. I loaded the above file into kdenlive and successfully rendered
to MPEG-2 and AVC MP4 with stereo audio.

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