when I watched videos on my mobile phone I never noticed any image artefacts. Most of the time I was connected to a Wi-Fi and the streaming protocol was HLS. On error the video just stopped, crashed or showed me a load indicator.
That’s why I would ask on which faults you can see image artefacts? If the streaming protocol or the device detect image artefacts in error cases? And which image artefacts you guys has seen.
Thanks!
Image artefacts are caused by errors in the video stream. The errors are a result of bad input stream, errors made by the encoder, errors during transfer and so on. Some errors are fatal, from others the decoder can recover - this depends on the decoder itself. IMHO android video capabilities are very poor.
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I have been trying to capture the screen from Android Emulator and record it to a .mp4 file. I adopted the standard approach of creating a virtual display and routing the frames to an encoder, multiplexing the video channel and writing to the an external storage. However, the ouput .mp4 file is just a blank screen when played back. The same code works when run on a device.
One observation is that the BufferInfo.size from onOutputBufferAvailable() always has a constant value of 13 or 2718 which clearly indicates trouble with the MediaCodec encoder. Should I change some parameters when configuring the encoder?
Another observation is from Logcat that tells me that a SoftAVCEncoder is used when running in an emulator, which kinda indicates that some software encoding is used but still not sure why this does not work.
I can access and view RTSP streams from IP cameras on Android via the VideoView component without problems.
Now I need to play the RTSP stream with a delay (i.e. if I specify a 30 second delay, the playback on screen should be 30 seconds behind the source and the delay needs to be variable though not during playback, only at the point of connecting to the source).
I originally thought this would not be a problem as I could simply change the RTSP buffer duration before connecting to the camera but unfortunately it seems the buffer size is baked into the firmware and cannot be changed in software. Now I have got a horrible feeling that my way forward will be to compile a version of FFMpeg for Android and somehow get the stream data out from the library, buffer it and then render it myself and I have no experience with FFMpeg.
I am unsure how I would now go about solving this problem and any help or pointers in the right direction would be greatly appreciated.
Update:
Sorry I forgot to mention, the RTSP stream is being accessed over WiFi on a LAN so no huge latency issues here from going over the Internet.
I'm trying to create an app to stream live TV. Currently the problem I'm facing is that after say 10 minutes of playing, the video will freeze but the audio will carry on. This is on a 1.3mbps stream. I also have lower streams, such as a 384kbps stream, that might last an hour or so, but will still do the same. I've tested this with a local video, that is high quality (file size is 2.3gb) and that has no lag and doesn't freeze at all, so it must be something to do with the way HLS is streamed to android.
Does anyone have any idea on how to solve this problem?
Thanks
We are writing an Android App on the Samsung Galaxy Tab. We have an Endoscope (Medical Surgery Camera) as DV-input and we want to live-stream the DV Video to the Tablet.
As a streaming server, we have the VLC player and a RTSP stream. The encoding works fine, and streaming over the network(rtsp) to another computer is good (< 1s). However, if we open the RTSP stream on the Galaxy Tab, there is a lag of 6-7s.
I have tried to set down the bitrate encoding (even the lowest doesn't work, the streaming lag results the same). So I think there must be some kind of network caching or video caching on the Android itself.
I googled and didn't find a way to disable or even modify caching on the videoview / mediacontroller.
Does anyone have an idea how to tweak the Android Streaming View?
Edit:
I figured out that it must be the internal buffer size that limits the video stream velocity. The LogCat tells me that AweSomePlayer is the Videoplayer in charge. So next question: How to change the awesomeplayer buffering size? I think it's written in cpp. How can I access this precompiled code via eclipse/java/android?
Does anybody have any luck streaming a high quality video (over 1000kbps) to Android through RTSP?
We currently have low quality video streams (around 200kbps) that work wonderfully over 3G. Now we are trying to serve a high-quality stream for when the user has a faster connection. The high quality videos play smoothly in VLC, but the Android playback seems to drop frames and get blocky, even on a 4 megabit connection.
It seems like the YouTube app uses a plain HTTP download for their high quality videos. This works well and plays smoothly, but will not work for streaming live videos. Has anybody had luck streaming high quality videos to Android through RTSP?
The videos are encoded using H.264, 1500kbps, 24fps, and a 720x480 resolution. In the app, we are using a VideoView to play the videos. We are using Darwin Streaming Server, but we are open to other options if necessary.
Update 6/23/2011
Looking through Darwin some more today. So far, I am just logging the request and session information in a Darwin module.
The original Droid tries to use these settings: 3GPP-Adaptation:...size=131072;target-time=4000. Although that means it wants 4 seconds of buffer, 131Kb only holds about a second of playback at 1200kbps. I understand that 1200kbps is large, but it is necessary for a high quality video (minimal compression on 720x480).
I am trying to force the client to buffer more, but I haven't figured out how to do that yet. I'm just looking through the Darwin Streaming Server source and trying to figure out how they do things. Any Darwin experts out there?
Update 6/24/2011
As it turns out, using plain old HTTP for viewing videos on demand works well with no loss of quality. When we get to live streaming, we will have to look more into RTSP.
Well even if the network is able to transmit at that rate, you still need to decode it. What are you using for decoding? You will probably need to use a NEON accelerated video decoder so you can have a proper framerate, and a decent size buffer... the graphics processor is only as good as the bus that it is in... Also what are your encoding settings and resolution?
Edit: You are encoding those at much to high bitrate, half of that will do fine. Also you need to make sure where the issue lies. Is the mediaPlayer getting the data and failing to stream at a decent framerate, in that case you have to replace the MediaPlayer code with your own player. Is it's network issue then only solution is to lower the bitrate, 600Kbps would be just fine (or 500Kbps video, 128Kbps audio), it's 3x your 200k stream and on a screen this small, the difference is not noticeable.