[Libav-user] Fwd: Help, Transcoding video

Carl Eugen Hoyos ceffmpeg at gmail.com
Thu Jan 24 00:21:33 EET 2019

2019-01-23 15:56 GMT+01:00, NDJORE BORIS <ndjoreboris at gmail.com>:

> I want to encode two times my input video file while decoding it juste one
> time.
> I use doc/examples/transcoding.c
> <https://ffmpeg.org/doxygen/trunk/doc_2examples_2transcoding_8c-example.html>
> What I want to do is to decode and encode like the transcoding.c examples
> does.
> Then, when I finished the decoding and encoding loop (while(1)).
> I want to call only the encoding function again in an other loop to encode
> a second time without
> decoding.
> Ex:
> First time :
> while(1)
> {
>        if (there is a frame in the input file)
>         {
>               decode input video;
>               encode output file;
>               next streamindex;
>          }
> }
> Second time :
> while(1)
> {       encode another outputfile;
> }
> What I want to know, is if it's possible to do that (decode only one time
> an input file in a whille loop and encode it two times).
> If yes, can you tell me how to do it ?

You can create a second encoder and call it with every decoded frame
parallel to the first encode.

If you want to encode sequentially this should also be possible but
please calculate first if the memory requirements are acceptable
for you - you need memory for all uncompressed frames, not
compressed as they are on your harddisk.

Carl Eugen

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