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matt.k · 20th October 2014, 23:18

Hi,

we got really stuck on this one. The stream is encoded using Intel QuickSync (hardware encoder) through VideoToolbox API on 2012 Macbook Air. It decodes without issues on older (A5, A6 based) iOS devices, but there are artifacts on A7, A8 devices. Video demonstrating the artifacts can be found here.

Actual stream is accessible here (HLS), or as individual segments (1, 2, 3, 4) that can be concatenated.

The encoding API doesn't give many options (turn B, P frames on/off, set bitrate, keyframe interval level and profile) and none of the options seems to have any impact on the decoding glitches.

One of the weird things about the issue is that it doesn't always happens. For example the video plays with glitches, but if it gets rewind and played again, it decodes properly.

Could anyone shed some light into this? Is there something fishy about the stream or is the decoder doing something wrong?

I'd be most grateful for any kind of response. We're also open to consulting offers if you feel like you can help us with this (in which case please send me a PM).

20th October 2014, 23:18	#1 \| Link
matt.k Registered User Join Date: Oct 2014 Posts: 4	Decoding artifacts on certain devices Hi, we got really stuck on this one. The stream is encoded using Intel QuickSync (hardware encoder) through VideoToolbox API on 2012 Macbook Air. It decodes without issues on older (A5, A6 based) iOS devices, but there are artifacts on A7, A8 devices. Video demonstrating the artifacts can be found here. Actual stream is accessible here (HLS), or as individual segments (1, 2, 3, 4) that can be concatenated. The encoding API doesn't give many options (turn B, P frames on/off, set bitrate, keyframe interval level and profile) and none of the options seems to have any impact on the decoding glitches. One of the weird things about the issue is that it doesn't always happens. For example the video plays with glitches, but if it gets rewind and played again, it decodes properly. Could anyone shed some light into this? Is there something fishy about the stream or is the decoder doing something wrong? I'd be most grateful for any kind of response. We're also open to consulting offers if you feel like you can help us with this (in which case please send me a PM).