How Can I Increase the Size of I-frames?

[rec]

I'm working with MPEG-2 in ffmpeg, and I want to increase the size of the I-frames while leaving the P-frames alone. Is there any way to do this?

:thanks:

[pandy]

I'm working with MPEG-2 in ffmpeg, and I want to increase the size of the I-frames while leaving the P-frames alone. Is there any way to do this?

:thanks:

Dual pass encoding, after first pass, modify quantizer for I frames (inside log).

Or use TMPEGenc, go to manual settings (compression setting > GOP structure > Force picture type settings > setting > right mouse button on each frame you want to change) and then freely select frame type and quantizer or bitrate.

[rec]

Could you please elaborate on what you mean by "modify quantizer" and how to do it.

[pandy]

Could you please elaborate on what you mean by "modify quantizer" and how to do it.

After 1 pass, ffmpeg provide log with information - modifying this information manually will allow you to control bitrate spent on I frames in 2 pass.

But i can't provide you ready to use prescription how to do it - almost each mpeg-2 encoder use own format for log and before modifying log you need to understand how it works - perhaps ffmpeg developer list can help you, perhaps you should check ffmpeg source to understand how log is created.

And be aware that manually modifying some values can affect encoding (buffer management) - perhaps some smart mpeg-2 guy can highlight this area more for you.

Fastest and most secure way to do this manually is IMHO use TMPGEnc v2.525.64.184 (latest revision for old TMPGEnc).