Sound plays but there is no picture
Three different faults produce this symptom and the player tells them apart. Two are not yours to fix, and knowing which is which saves the evening.
Audio playing over a blank screen is 1 symptom with at least 3 causes, and they have almost nothing in common. The player already tells them apart. Working out which one you have is most of the fix.
The three faults
F5 VideoFreeze the picture stopped on a frame, audio continues
F7 BlackFrames the picture is updating fine, it is just black
F4 DemuxStarve bytes arriving, no frames coming out at all
They feel identical from the sofa. Underneath they are entirely different.
F5 is a stalled decoder or presentation path. The last frame is still on screen; the picture is not black, it is stuck. If you can see a frozen image rather than blackness, this is yours.
F7 is the one people misdiagnose most. Everything is working: bytes arrive, the demuxer produces frames, the decoder decodes them, they are presented on schedule. The frames are black. This is almost always the source, most commonly a channel that is off air, showing a black slate.
F4 is a stream sending padding instead of content. The byte rate looks normal, which is the confusing part, but no frames come out.
Why black is hard to catch, and what we do about it
F7 shows why this cannot be detected the easy way.
Every counter-based rule works on deltas: bytes read, frames decoded, pictures displayed. A stream feeding black advances all of them perfectly. Frames are decoded and displayed exactly on time. Nothing in the statistics differs from a healthy channel.
So the only way to catch it is to look at pixels. The probe takes a 96 by 54 snapshot rather than a full frame and counts a pixel as black at a luma of 24 or below on a 0 to 255 scale. A verdict needs 98 percent of those pixels black and a luma standard deviation at or below 4.0, held across 4 consecutive samples taken 1500 milliseconds apart. The standard deviation does specific work there. Without it a genuinely dark scene in a film would score as black; a dark scene has structure and a black slate does not.
The original spec probed only when something looked suspicious, and that had the check in the wrong place. A channel that opens black is not suspicious by any counter measure, so under that rule it would never have been examined at all. One probe now runs immediately after playback reports healthy, for exactly that case.
And once a black-frame recovery has failed and black is confirmed again, further black-frame recoveries are suppressed for 10 minutes. Restarting a source that is genuinely off air is churn, and churn on a live stream costs a provider connection every time.
What to do about each
If the picture is frozen on a frame (F5): change channel and come back. If it recovers, it was transient. If the same channel freezes at the same point repeatedly, it is the source.
If the picture is black (F7): check whether the channel is meant to be on air. Many channels close overnight and show black rather than a caption. If another channel from the same provider is fine, you have your answer, and there is nothing to fix.
If nothing is coming out at all (F4): a provider-side fault, and the distinctive sign is that your bandwidth looks normal. The stream is sending program tables and padding, which holds the byte rate while carrying no content. No setting on your machine changes this.
Notice that 2 of the 3 are not yours. That is the useful part of the classification: it stops you spending an hour on your network for a problem that is upstream.
The fourth cause, which really is a codec problem
If audio plays and there is no picture on one specific device while the same channel is fine on another, you are probably looking at a decoder that cannot handle the video. The clearest case is AV1 on a console, whose player build carries no AV1 hardware decoder, so it falls back to software, and software-decoding high-resolution AV1 on console hardware does not keep up. A recent Windows machine decodes the same channel in hardware without effort.
Check the codec in the stream information panel. Why some channels work on Windows but not on Xbox covers the platform differences, H.264, HEVC and AV1 covers what each one demands, and for the full detection mechanics, including why a frozen picture never raises a player error, video freezes, audio continues.
What this article measured22 claims, each with the evidence behind it
| Claim | Evidence | Counted |
|---|---|---|
| Three of the nine classified faults present as sound without picture, and they are distinguished rather than merged: a stalled picture, a black picture from a healthy pipeline, and a demuxer producing nothing. | n = 3 | Aug 31, 2026 |
| A black-frame verdict needs 98 percent of pixels black with a luma standard deviation at or below 4.0, sustained over 4 consecutive samples taken 1500 milliseconds apart. | n = 1 | Aug 31, 2026 |
| One black-frame probe runs immediately after playback reports healthy, because a stream that opens black never trips the counter rules at all: the counters advance perfectly on black frames. | n = 1 | Aug 31, 2026 |
| After a failed black-frame recovery confirms black again, further black-frame recoveries are suppressed for 10 minutes, because retrying a source that is genuinely feeding black is churn. | n = 1 | Aug 31, 2026 |
| A starved demuxer has to persist for 6 seconds before it is declared, the longest of the four main verdict windows, which are otherwise 4 seconds each. | n = 4 | Aug 31, 2026 |
| A stream reduced to program tables and padding holds its byte rate while producing no frames, which is why bandwidth graphs look healthy during this fault. | n = 1 | Aug 16, 2026 |
| The black-frame probe works on a 96 by 54 snapshot rather than a full frame, which is enough to measure how much of the picture is dark without the cost of capturing a 4K image every 1.5 seconds. | n = 1 | Sep 1, 2026 |
| A pixel counts as black at a luma of 24 or below on a 0 to 255 scale, so the test is for near-black rather than for absolute zero. | n = 1 | Sep 1, 2026 |
| The probe allows 1 second for a snapshot, and a timeout is treated as evidence that the video output is wedged rather than as an error to report. | n = 1 | Sep 1, 2026 |
| The black-frame probe carries its own master flag, separate from the detector's overall mode, and defaults to on. | n = 1 | Sep 1, 2026 |
| A video stream disappearing within 5 seconds of reaching presentation is treated as programme-table churn, common right after opening an IPTV panel, and only raises suspicion. After that window the same event is an immediate freeze verdict. | n = 1 | Sep 1, 2026 |
| When no video stream, no video output and advancing audio persist for 4 seconds, the session is classified audio-only and the video rules are disarmed, so a radio station is not condemned as a black picture. | n = 1 | Sep 1, 2026 |
| Channels measured as low frame rate during a 30 second calibration get a 15 second freeze window instead of 4, because a slate that updates rarely is not a frozen picture. | n = 2 | Sep 1, 2026 |
| Visible corruption shortens the freeze windows: 3 discontinuities or 25 corrupted units in a single sample keep the shortened windows armed for 10 seconds. | n = 3 | Sep 1, 2026 |
| The fault class selects which rung of the recovery ladder runs, so a black picture and a stalled picture are not merely labelled differently, they are recovered differently. | n = 1 | Sep 1, 2026 |
| One of the nine classes exists only as corroboration: a stopped input clock is documented as a corroborating signal and never a verdict on its own. | n = 1 | Sep 1, 2026 |
| For 10 seconds after a recovery attempt, the number of consecutive black samples needed for a verdict is halved along with the other windows, so a source that comes back black is re-condemned faster. | n = 1 | Sep 1, 2026 |
| A live stream that simply ends without the viewer asking is classified separately from one that errors, because a clean end-of-stream on live television is a fault rather than a completion. | n = 1 | Sep 1, 2026 |
| Before concluding a picture is missing, note that the player exposes 6 aspect modes and a zoom from 0.5 to 2.0, so a picture can be present and framed off-screen. | n = 6 | Sep 1, 2026 |
| Repeated rebuffering is detected independently of the freeze rules, counted only below 62 percent cache and cleared at 88, with 4 episodes in a 60 second window declaring a loop. | n = 4 | Sep 1, 2026 |
| Nothing is judged until a stream has had its opening budget: 15 seconds to reach first presentation on a cold open, 8 on a recovery attempt. | n = 2 | Sep 1, 2026 |
| The console's player build carries no AV1 hardware decoder, so an AV1 channel falls back to software there and can fail to keep up where the same channel is fine on Windows. | n = 1 | Aug 23, 2026 |