[Libav-user] Adjust fps

Carl Eugen Hoyos ceffmpeg at gmail.com
Fri Sep 9 18:53:08 EEST 2016

2016-09-09 13:57 GMT+02:00 Leandro Raffo <ljraffo at gmail.com>:
> 2016-09-09 6:55 GMT-03:00 Carl Eugen Hoyos <ceffmpeg at gmail.com>:

>>>>> I see, but I wanted to avoid doing a decode/encode stage.
>>>>> Guess its not possible then.
>>>> It generally is possible, depends only on the codec.
>>> I'm trying to apply it to H264 and HEVC codecs.
>> It may be possible if the (output) streams only contain I-frames,
>> I am not sure if there are timestamp-related issues.
>> (It is not possible to randomly drop and keep non-I-frames.)
> I see there is the Keyframe flag in AVPacket, so sending
> keyframes to av_write_interleaved_frame (Is
> av_write_frame equivalent in this case?) would be as you say.
> But isn't there a way to see if I'm getting B or P-frames in case
> I don't get enough I-frames?

AVFrame->pict_type tells you the type of frames.

Please test with -skip_frame nointra if this is usable for you
before investing more time.
When doing this, you can also test -skip_frame noref
which may be an alternative: Drop those (h264) frames
that will not be needed to decode future frames. I am
not sure if this information is available outside libavcodec,
you may have to do some additional programing.

Carl Eugen

More information about the Libav-user mailing list