Hello everyone, First some context (just to answer your questions Thilo): ------------------- I'm working on a piece of Software called Ring (http://ring.cx), and we are using Libav for video encoding/decoding (not audio) on Mac OSX platform. When I looked at ffmpeg and libav I saw that Libav had no support on video devices, and started to talk with them about this issue.
I had two choices: Either move to ffmpeg and use the existing implementation, or implement it in libav. Luca offered to help me on implementing it to libav, and set up basic context for me, using ARC etc. Of course I looked into ffmpeg implementation, I mean this piece of code was basically what I wanted. I looked at other avdevices in libav as well. I agree you should be mentionned in the credits. I'm truly sorry for not thinking about it earlier, and it is true your work helped me a lot. Why I only implemented video? ----------------------------- The only reason is time. I needed video support, no audio or screen capture. Adding audio would be very cool. But concerning screen capture, I do not think it should be added here, explanation below. What's next? ------------ I would gladly collaborate on merging the changes to ffmpeg's implementation in a new fork where we could both work on. If this contribution can create a collaboration between the two projects, it would be a nice move. My next wish, that I haven't fully discussed with the libav team is creating a new avdevice for screen capture (yes, now I have time for that). As v4l2 and x11grab are two separated devices I want to do the same for OSX. Adding everything in the same avdevice is too much in my opinion, since I would like to supply different options (grabbing a rect screen, a window, or a full display). @Thilo: If this sounds ok to you we could discuss further privately and work together. AL ----- Mail original ----- > De: "Thilo Borgmann" <[email protected]> > À: "libav development" <[email protected]>, "Alexandre Lision" > <[email protected]> > Envoyé: Jeudi 26 Novembre 2015 06:45:16 > Objet: Re: [libav-devel] [PATCH v3 0/3] OSX video support > Am 26.11.15 um 07:12 schrieb Luca Barbato: >> On 25/11/15 09:15, Thilo Borgmann wrote: >>> Hi folks, >>> >>> I wonder why you have done a reimplementation based on FFmpeg's device with >>> reduced features and OS support. Can you enlighten me? >> >> The current implementation from Alexandre and the one from you are quite >> different: > >> - This one references the devices using their stable names, your seems >> to use some index. >> - This one uses ARC, yours uses autorelease pools. >> - This one is just for video capture so far, yours is >> audio+video+screen_capture. > > a) True. Although I don't share your opinion that this makes the > implementations > 'quite different'. > >> Probably during his initial tries he used more code from yours, but the >> final version[1] I'm looking at keeps from your implementation just the >> pixel format -> CoreVideo formats table... > > b) False. The very core is equal: Run-time approach for format detection, > frame > receiver delegate, frame buffering in context, thread synchronization, PTS/DTS > generation... all the same, all copied. > >> Surely you should be credited in the patch, but yours and Alexandre's >> are quite different implementations and from what I can read, you >> wouldn't move to ARC so I guess their purposes are even different. > > c) For proper credit you should have started to add the device from FFmpeg > into > the Libav tree; then apply your patches to remove what you didn't like; then > apply your patches to add what you want in addition or what you want to change > (for example ARC); and then add your copyrights next to the existing one > (mine). > d) I wrote because I wanted to know the reason for a reimplementation and that > question has not been addressed. I can't see a reason. Also, I wonder why you > are talking about Alexandre's implementation while you are listed yourself as > the first author. > > > However, I'm not writing because of a nor b nor c nor d. I don't really care > and > please let us not discuss a,b,c or d any further. Stop. Please. > > > Instead, I want to offer both of you to collaborate on this device. Let's > setup > a github-based FFmpeg branch, patch the FFmpeg device towards ARC, discuss and > apply further changes you did in the Libav implementation, setup another Libav > branch, pull over the device and if you still don't want audio&screen drop it > - > finally we can pull that device into FFmpeg|Libav HEAD. > > I would very much like to see this happen in the aftermath of VDD 2015 and > have > finally avoided yet another useless divergence between FFmpeg and Libav. > > This is my honest offer. Now, it is up to you two to collaborate or not. > > -Thilo > > p.s. That you pulled the device into Libav an hour or so ago although review > on > libav-devel is still in progress does not change anything regarding my offer > nor > does it prevent us from doing it. > > p.p.s. I keep Alexandre in CC just because I don't know if he follows on > libav-devel and can read this. Sorry for spam if you do, Alexandre. _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
