A codec is the compression scheme your phone uses to squeeze music down small enough to cross a Bluetooth link.
Bluetooth is a narrow pipe. A CD-quality stream is roughly 1,400 kbps and the pipe reliably carries a fraction of that.
So something has to be thrown away, and the codec decides what.
That is the whole of it. The rest is marketing.
Both ends must speak the same codec, or you drop to SBC
This is the fact that resolves most of the confusion.
A codec is a negotiation between two devices. If your phone does not support it, the headphones cannot use it.
An iPhone handles SBC and AAC and nothing else. LDAC printed on the box of a pair of headphones is, for that owner, decoration.
Android phones vary by chipset. Qualcomm silicon carries aptX; LDAC has shipped in Android itself since version 8.
When the negotiation fails, both ends fall back to SBC, which every Bluetooth audio device on earth supports.
| Codec | Peak bitrate | Where you find it |
|---|---|---|
| SBC | ~328 kbps | Universal fallback, every device |
| AAC | ~256 kbps | iPhone and iPad, patchy on Android |
| aptX Adaptive | 279โ420 kbps | Qualcomm-based Android phones |
| LDAC | 330โ990 kbps | Sony headphones, Android 8 and later |
| LC3 | 160โ345 kbps | LE Audio devices, Bluetooth 5.2 onward |
The audible gap between them is smaller than the numbers suggest
LDAC at its top setting carries three times the data of SBC. It does not deliver three times the sound.
Listening tests repeatedly show trained listeners struggling to separate a good AAC or aptX stream from LDAC on the same headphones.
The reason is that the driver, the earpad seal and the manufacturer's tuning shape the sound far more than the last hundred kilobits.
Change the codec and you might notice. Change the headphones and you certainly will.
None of these formats is lossless, whatever the badge on the box implies.
A hi-res logo on a wireless product describes the input the codec accepts, not what survives the journey.
Older SBC implementations were genuinely poor, which is where the codec's reputation comes from. Modern ones run near the top of their range and sound respectable.
Latency and stability are where the real difference sits
Watch a film on a tablet over plain SBC and lips run ahead of the dialogue by a noticeable margin.
aptX Adaptive and LC3 cut that delay substantially, which matters for video and makes casual gaming tolerable.
Stability is the other honest advantage, and it works the opposite way to intuition.
LDAC running at 990 kbps is the most fragile setting on your phone. On a busy platform, with hundreds of competing radios, it stutters.
Sony's own control app therefore offers a connection priority mode, which pins the stream to 330 kbps and simply holds.
Battery life follows the same curve. A higher bitrate keeps both radios working harder and shortens a quoted figure by a couple of hours.
Our Sony WH-1000XM5 review: 5 numbers that explain why it still sells in 2026 covers how that trade-off plays out over a full charge.
Buy for the fit and the noise cancelling, then check the codec
Order the decision properly and the codec question mostly answers itself.
Comfort over three hours, the quality of the noise cancelling and the seal against your head decide whether you enjoy a pair of headphones.
Codec support is a tie-breaker between two models you already like.
If you carry an iPhone, confirm decent AAC handling and ignore the aptX and LDAC lines entirely.
If you carry a recent Android phone, LDAC or aptX Adaptive is a small, genuine bonus rather than a reason to spend another ยฃ80.
And if a shop assistant leads with the codec rather than the fit, you are being sold the specification sheet.
