Thanks, Ronald, will try to do futher reading in that direction. 2011/8/11 Ronald S. Bultje <[email protected]>
> Hi, > > On Mon, Aug 8, 2011 at 10:31 AM, Vadim Gusev <[email protected]> wrote: > > Hi there. I'm wondering if it's possible to find solution for situation > i'm > > in right now. I need to modify existing app, that uses ffmpeg to > > decode/encode video so it will work with encrypted files. > > Basically i have encrypted video file, that i need to process, transcode > and > > encrypt output stream. The goal is to not to store decrypted file but > > decrypt, transcode and encrypt on the fly. > > File is encrypted with twofish cipher. The main problem i see is: packets > > size differs so i can not know how much should i decrypt and supply to > libav > > on each iteraton. > > So the question is how to deal with situation where input file is not > > actually a video file that can be supplied directly to libav, but should > be > > pre-processed (decrypted in my case) and it can't be pre-processed at > once > > entirely. > > In other words, can I create sort of pipe which looks like: "read input > file > > | decrypt | decode | process | encode | write output file". > > > > Thanks in advance. > > If you intend to do the decrypting outside libav, you can look into > using an AVIOContext. This is a structure that basically wraps our > read/write/seek routines, you can basically make the read callback do > the decryting on the fly and block while that's in progress. Supply it > as AVFormatContext->pb while opening the media > (av_open_input_stream()) and it'll work as you expect. > > Output encrypting is easy so I guess I won't go into that. > > Ronald > _______________________________________________ > libav-api mailing list > [email protected] > https://lists.libav.org/mailman/listinfo/libav-api >
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