FA-11261 / Media timeline seeking / Open access
Playback rate wall to media delta · case 01
The media timeline advances at normal speed regardless of playback rate.
ROOT CAUSE
The media timeline advances at normal speed regardless of playback rate.
VERIFIED REPAIR
Preserve the media contract: Advance media position by nonnegative wall-time delta times nonnegative playback rate; zero rate freezes position.
Unsuccessful approach: Dividing by rate reverses faster and slower playback behavior.
Case contract
Advance media position by nonnegative wall-time delta times nonnegative playback rate; zero rate freezes position.
Why this case matters
A deterministic local media controller stage; metadata and downloaded data are supplied explicitly. No external player, service or codec is required.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(position, wall_delta, rate):
return position+wall_delta
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(10, 2, 2)),14)
check('fixture 2',solve(*(10, 2, 0.5)),11)
check('fixture 3',solve(*(10, 2, 0)),10)
check('fixture 4',solve(*(0, 0, 1)),0)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | 12 | 14 | Failed |
| fixture 2 | 12 | 11 | Failed |
| fixture 3 | 12 | 10 | Failed |
| fixture 4 | 0 | 0 | Passed |
SHA-256 / ff2496675dfca5eb29706e7496cb2b49b7b475ff83ddb0603735ada9fa2c6c27
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(position, wall_delta, rate):
return position+wall_delta/rate if rate else position
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(10, 2, 2)),14)
check('fixture 2',solve(*(10, 2, 0.5)),11)
check('fixture 3',solve(*(10, 2, 0)),10)
check('fixture 4',solve(*(0, 0, 1)),0)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | 11.0 | 14 | Failed |
| fixture 2 | 14.0 | 11 | Failed |
| fixture 3 | 10 | 10 | Passed |
| fixture 4 | 0.0 | 0 | Passed |
SHA-256 / 986d32d8bfed52bff9d7e23e241cc6d6c15cb1d16a1100dd10620ec90ae2d67a
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(position, wall_delta, rate):
return position+wall_delta*rate
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(10, 2, 2)),14)
check('fixture 2',solve(*(10, 2, 0.5)),11)
check('fixture 3',solve(*(10, 2, 0)),10)
check('fixture 4',solve(*(0, 0, 1)),0)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | 14 | 14 | Passed |
| fixture 2 | 11.0 | 11 | Passed |
| fixture 3 | 10 | 10 | Passed |
| fixture 4 | 0 | 0 | Passed |
SHA-256 / 9f3b4d4a21897c9715a163903ff2f7063894fdae78235373efb4efe6e3721a6c
Verification & scope
This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.
Observations recorded using Python 3.12.14 at 2026-09-29T14:38:46.303983+00:00.
Case digest / 54babffdfb212045bfb1ef21d5f56e92978ac9fee30757eeff237d7acbd71811