Audio coming from certain content providers or devices (Netflix, Roku, Apple TV etc.) typically use an advanced digital audio signal such as HDMI or advanced Dolby audio. These cannot be translated into analog or PCM by most television software and so the signal is not passed through into the headphones. As a result you may get silence or audio from a different source like your cable box.
In order to resolve this, you will you will need to change the audio output format in the app or device to PCM (may be in the smart hub on some TVs) or you will need a digital to analog decoder. The Digital to Analog Decoder will take the advanced digital signal and decode it into an analog signal that your headphones can utilize.
You will not lose audio quality as the digital signal is a carrier signal only. Any audio you hear from your TV speakers, sound bar or headphones is an analog signal. The digital signal is translated by the TV, receiver or other device by the time it reaches the transducers. The only difference is where the audio signal is translated.
If your digital optical output is not in use we recommend the OREI DA34. The OREI DA 34 can be seen here: (http://www.amazon.com/Orei-DA34-Digital-5-1-Channel-Headphone/dp/B008EPW7O0/ref=sr_1_1?ie=UTF8&qid=1407330599&sr=8-1&keywords=OREI+DA+34).
If the digital optical output is already being used by a device like a sound bar you will want the J-TECH Digital to Analog Decoder because it offers both an analog output for the headphones to use and an optical output for the soundbar (or other device) to use. The J-TECH can be seen here: (http://www.amazon.com/J-Tech-Digital-JTDDBSW0301-Decoder-5-1-Channel/dp/B00L3OZK1G/ref=sr_1_1?ie=UTF8&qid=1428599714&sr=8-1&keywords=jtech+digital+to+analog+decoder).
Please bear in mind that we recommend these specific devices because we have tested them and know that they work. We do not recommend digital to analog CONVERTERS (a different device entirely) because they cannot translate the more complex digital audio signals.
NOTE: We do suggest looking at your TV's documentation to make sure that there are no design features that prevent certain digital signals (like HDMI signals) from being output through the Digital Optical output before purchase. It is possible for this feature to exist but exceedingly rare so for most applications the Digital to Analog DECODER is the optimum solution.