[Libav-user] Encoding with variable frame rate

Kalileo kalileo at universalx.net
Tue May 21 18:34:04 CEST 2013

On May 21, 2013, at 22:53 , Brad O'Hearne wrote:

> On May 21, 2013, at 7:26 AM, Kalileo <kalileo at universalx.net> wrote:
>> Which "Playback" , which player ? Every player can have it's own playback logic, nevertheless I don't see where the player logic would require fps to be fixed (unless it ignores dts/pts).
> I reproduced this behavior by with playback in Wondershare Video Converter Ultimate, VLC, and streaming through Wowza and playback in a browser Flash player. All consistent. 

Which might simply say that these tools do require a fixed frame rate, or need longer to synchronize, than you gave them time, or that your dts/pts settings were wrong.

> 1. Does FFmpeg support variable frame rate, or not? 

ffmpeg gives you the tools to handle it. Don't mix statements about ffmpeg command line tool with what you can do with the ffmpeg libraries.

> 2. If I set the time_base.den on the video codec (let's say to 30 fps), can I fire  say 12fps at the encoder and compensate for that by setting pts/dts such that the timing won't be incorrect? 

Again, that depends on your player, on how it synchronizes.

Don't blame it on ffmpeg when your players / streamers can't handle it.

You might want to study the basic old example of a player written using the ffmpeg libraries by Dranger. Seriously.

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