Show HN: Kickflip – Open Source Live Mobile Video Streaming SDKs
kickflip.io
kickflip.io
Rich from Kickflip here. We've been working really hard on this for a long time and are super happy to get to announce it today.
Kickflip is some really cool tech - we've lowered the cost of mobile video broadcasting by orders of magnitude, and we've opened it up to everybody!
If you've got any questions or feedback, let me know and I'll be happy to answer them.
Thanks very much!
Has the scenario on the open API changed ? I would guess not. Congrats for taking care of this.
The main trick is to encode only video frames in your temporary .mp4 file, and to make an additional 1 frame .mp4 file for extracting the avcC record.
It is worth nothing that this is definitely a broadcast-first technology (at least for now), meaning that it's designed for delivering a high quality stream which will be seen by a large audience, rather than a low quality stream to an indivudual audience with a short amount of latency.
(Ok, it's actually just because it's an awesome trick. The 720p thing is just a coincidence.)
Congrats guys, looks awesome.
All of our streams are HLS rather than RTMP, although we do have RTMP support working in the SDKs, we don't plan on making that a priority product focus right now - HLS and DASH are the future. Kickflip will likely officially support RTMP in the 1.1 versions of the SDKs.
Thanks again for your support!
I also haven't really encountered much of an issue with frame reordering, but as it is I mostly don't care about that. I have noticed, however, that as of iOS 7.0.4 or so the encoder can output multiple slices per frame which it previously didn't do (or at least I never caught it doing it anyway)
The python library and client is still work in progress.
Still, I've open sourced the repo so those who are curious can take a peek, although there isn't much worth showing there yet. We'll make a larger announcement when that happens.. there's a lot of stuff we've got planned for the desktop yet.
Here's the fixed link: https://github.com/Kickflip/python-kickflip
To put this in perspective, three live encodes/ streams (360P, 540P, 720P) using Wirecast on a high end Macbook Pro pegs the CPU around 60% and requires at least 5MBPS upstream.
I understand the financial reasons for this architecture - cloud-based transcoders are crazy expensive - but from a customer satisfaction POV it's not an easy project.
Encoding and upstreaming a single 640p video does seem plausible. But for each additional encode you need HLS and RTMP, and both CPU and upstream bandwidth grow linearly with each encode. A single bitrate means HLS and RTMP - two encodes, two upstreams. (Only HLS means only Apple software - 20% of the mobile market, 5% of the desktop market).
For example, for h.264, once you get the NAL units from the encoder (which in the case of iOS is a chip provided by PowerVR) you can encapsulate them in whatever format you need...mpeg-ts, MP4, RTMP, RTP, it doesn't matter...
I only support one simultaneous encode in my SDK, and I'm not actually sure how many the hardware would support as an upper limit.
It's possible to perform a single encode per bitrate, then split it between Flash and HLS on the server side, but then again that already exists in the form of cloud-based transcoders.
It's also possible to take that single encode - h.264, for example - and wrap it twice, once for MP4 and once for HLS, but that would be software, which is CPU intensive. If it's in software, it's not in hardware.
The SoCs included with virtually every mobile device today have circuits designed specifically for encoding/decoding H.264 video and AAC audio. This is how your mobile device's native camera app reliably records HD video. Whether it's 640p or 1080p, there isn't a significant drain on system resources.
These chips were traditionally accessed via a standard OMX[1] library (Think OpenGL for Video hardware), but the OMX implementations were device specific, making it nearly impossible to write custom video software with mass market appeal.
Just recently (July '13 on Android), the video hardware has become somewhat controllable by the standard Android / iOS platform APIs allowing us to write a truly compatible video product.
We currently only offer single stream output. When we do offer multiple bitrate outputs (transcoding), we'll do that work serverside.
You push a single stream, which any client can already do, and they can already live without transcodes. Your app doesn't add value by freeing them from the cost of cloud-based transcoders.
I'm excited for our open-source Android and iOS clients to stimulate development of some novel video apps. Maybe Security monitoring systems or even Phone + $20 Weather balloon = Weather satellite!
It does use more bandwidth, since the streams are higher quality than other methods, but that's . It's also configurable.. it doesn't _have_ to be higher quality. Implementers can choose to lower the resolution.
All in all, this is definitely a better solution for developers and clients.
The streams are not higher quality than other methods. Your 720P is the same as everybody elses.
This is a great opportunity for a future blog post in which we explore the differences you're bringing up!
This change seems highly correlated with the change of hands. I thought this would be a temporary phase, but seems to have become worse with time. I think a line of over-moderation is being crossed here.
I would try and flag my own comment so that it gets some attention. EDIT: Unfortunately it seems one cannot do that, but if you agree, and can flag this, please do.
https://news.ycombinator.com/item?id=7605973
https://news.ycombinator.com/item?id=7619287
https://news.ycombinator.com/item?id=7611148
https://news.ycombinator.com/item?id=7608102
https://news.ycombinator.com/item?id=7642127
You'll notice that I've written a lot about the community practice of corrective upvotes, which is the best antidote to unfairly faded-out comments. This practice works most of the time. For example, the comment score you're complaining about was corrected hours ago. Corrective upvotes work because few such comments go far into negative territory. They're the best solution because they fix most of these problems silently.
The reason the guidelines ask you not to post complaints about downvoting is that those, by contrast, stick around forever, worsening the threads.
I am well aware of your position, and I do try to correct comments that I feel were unfairly down-voted. However, I dont like this solution at all.
> For example, the comment score you're complaining about was corrected hours ago.
I had upvoted it to compensate for the downvote myself. If this was a single instance I would have moved on. I am seeing this too frequently and I dont see how else I can bring this to your attention. (If there is an alternative please do mention, Would be happy with a Ask dang page.)
A downvote is unfriendly (although sometimes it is indeed deserved). An unfair downvote may or may not get corrected, and now I can only correct it and not give it a positive karma that I otherwise would have liked to. That does not seem to have been the HN way.
It still would have been fine if the downvote pattern would have been as before.
Compensatory upvote has been a part of HN since ever. It is not a new invention.
Its the recent uptick in downvotes on perfectly benign comments (not mine) that is bothering me.
What is bothering me is that I noticed that downvoting has acquired a distinct hair trigger edge and a tendency leaning towards petty disagreements. There is a heavy feeling of over moderation in several threads. I am not an old timer by any means but have been around for a while to know that this feels very alien on HN, unsavory too.
On the contrary, this mythical "highly toxic comment" that is being used to justify the change I have seen very little of. Far rarer than a new story with half the comments greyed out, for the entire night.
I love spending time here, I am sure you would want HN to be something like that, so wanted to bring this to your attention even though I was sure this will get downvoted. If this causes some reflection, thats a tiny cost to pay.
Finally, like with system administration, good moderation is one that is barely noticed. I sense things are getting a little overboard. Just an FYI
That's easy: email hn@ycombinator.com, as the guidelines say.
"Heavy feeling of over-moderation" seems to suggest that you think we're the ones doing most of the downvoting. We're not, of course; users are.
Excellent! have overlooked this, and thanks for responding.
> We're not,
Never doubted that.
On the product I work on, we already have our own house built media server and rtmp restreamer. As to not supporting RTMP, in our experience RTMP had much lower latency, which resulted in us switching away from HLS wherever possible.
I don't actually work on the mobile streaming side of things, I work on the web side, particularly the video player.
It's also bandwidth adaptive streaming, backed by a global CDN, and generates both Live and VOD HLS streams.
But, more importantly, we've designed it in such a way that as a developer, you don't even have to worry about that! The library just exposes a really simple API that does all of the video magic for you.
Kickflip currently requires iOS 7 and works on any iOS device which supports iOS 7.
The Android requirements are a bit steeper, unfortunately: Android needs at least 4.3, as that's when the hardware encoder access API which we use was introduced.