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I have android tv application playing 2 different videos udp streaming using Exoplayer, the below images(image1 and image2) show the specifications of every video .. First one with low resolution play well without any problem in buffering, the second one have bad buffering and streaming.

image 1 : the first video with lower resolution (1280x720) which is playing well without any freezing or problem

this is the specifications of first video with resolution 1280x720

image 2 : the second video with high resolution (1920x1080) play with freezing, or incontinious buffering this is the specifications of second video which have the problem in buffering or streaming

Below is my exoplayer initialisation

   ExoPlayer.Builder playerbuilder = new ExoPlayer.Builder(WelcomeActivity.this);
    LoadControl loadControl = new DefaultLoadControl.Builder()
            .setBufferDurationsMs(15000, 50000, 2000, 5000)
            .setTargetBufferBytes(DefaultLoadControl.DEFAULT_TARGET_BUFFER_BYTES)
            .setAllocator(new DefaultAllocator(true, C.DEFAULT_BUFFER_SEGMENT_SIZE))
            .setPrioritizeTimeOverSizeThresholds(DefaultLoadControl.DEFAULT_PRIORITIZE_TIME_OVER_SIZE_THRESHOLDS)
            .build();


    player = playerbuilder .setLoadControl(loadControl).setRenderersFactory(buildRenderersFactory(WelcomeActivity.this)).build();      
    player.setTrackSelectionParameters(
            player.getTrackSelectionParameters()
                    .buildUpon()

                    .setMaxVideoSize(1280, 720)
                    .setPreferredTextLanguage("ar")
                    .build());

As you notice i am setting the maximum video size to low resolution .setMaxVideoSize(1280, 720) but this not changing any thing regards the bad buffering of the second video with high resolution

Malo
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    The higher resolution video likely has a higher bit rate and hence is more susceptible to network delays. Is this not what you mean - i.e. is there some other issue you are flagging? – Mick Feb 13 '23 at 14:57
  • This is exactly what the problem is...so if i make the bit rate lower can this solve the problem??? And what is the default value of bit rate ? How to make it lower ? Thank u – Malo Feb 15 '23 at 10:26
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    You will need to encode it to get a lower bit rate. I'dd add some details in an answer - too much for a comment. – Mick Feb 15 '23 at 10:55

1 Answers1

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The size and bit rate of an encoded video is determined by how it is encoded - e.g. what codec is used and what parameters and configuration the encoding uses.

Nearly all encoders try to reduce the size of the encoded video, to make it easier to store and to transmit, and there is a balance between the size reduction and the visual quality of the video when it is subsequently decoded and played.

Generally, smaller size/bit rate means less quality, but it does depend on the content itself - for example some cartoons are very tolerant of lower bit rates. More advanced commercial encoders can do 'context aware' encoding and adjust the quality and bit rate depending on the scenes.

The most common codec at this time is the h.264 codec and ffmpeg is probably the most common open source tool for encoding.

ffmpeg provides a guide for encoding videos, or re-encoding / transcoding videos with h.264 and this includes notes and examples on quality vs bit rate trade off:

The two key sections in the above are for Constant Rate Factor encoding and two pass encoding.

CRF

allows the encoder to attempt to achieve a certain output quality for the whole file when output file size is of less importance. This provides maximum compression efficiency with a single pass

Two Pass

Use this rate control mode if you are targeting a specific output file size, and if output quality from frame to frame is of less importance

There is also a note on Constrained encoding (VBV / maximum bit rate) which it would be good to look at too.

I think you might be best to start with CRF encoding and experiment with the CRF value to see if you can find a quality/bit rate combination you are happy with.

Finally, it would be worth you checking out ABR streaming also, especially if you plan to host many videos and want your users to have consistent experience. For ABR you create multiple copies of the video, each encoded with different resolution/bit rate.

The client device or player downloads the video in chunks, e.g 10 second chunks, and selects the next chunk from the bit rate most appropriate to the current network conditions. See some more info in this answer also: https://stackoverflow.com/a/42365034/334402

Mick
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  • already i have build ffmpeg extension for my exoplayer to decode the audio of video streaming because some of my devices doesnt support the audio track... so technically .. what is the step i need to follow to encode my video using ffmpeg ?? – Malo Feb 15 '23 at 11:18
  • Also how the selection of `DefaultBandwidthMeter` can help in my case ?`final long defaultMaxInitialBitrate = Integer.MIN_VALUE; final DefaultBandwidthMeter defaultBandwidthMeter = new DefaultBandwidthMeter.Builder(WelcomeActivity.this) .setInitialBitrateEstimate(defaultMaxInitialBitrate) .build();` – Malo Feb 15 '23 at 11:20
  • It sounds like you have some non standard encoding so it might be best to take your video and reencode into a more standard Android supported format, usually h.264 for video and aac for audio - see here: https://developer.android.com/guide/topics/media/media-formats#video-encoding. You can use the ffmpeg encoding guide in the link above and experiment with bit rates to find one that works. You could also go to ABR (HLS /DASH) - if you do this look at the Shaka Packager: https://github.com/shaka-project/shaka-packager (check out the documentation links) – Mick Feb 16 '23 at 10:51