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media: iris: disable time-delta-based rate control for VBR

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The iris encoder driver was not sending
HFI_PROP_TIME_DELTA_BASED_RATE_CONTROL to the firmware during encoder
initialization. Without this property, the firmware defaults to
time-delta-based rate control (enabled), which calculates the output
bitrate from actual frame timing rather than following the configured
bitrate target.
This caused variable bitrate (VBR) encoding to produce ~5x configured
bitrate. For example, with video_bitrate=896000 (896 Kbps), the output
is ~4.4 Mbps instead of the expected ~896 Kbps.
Time-delta-based rate control is designed for variable frame rate (VFR)
scenarios where the encoder adapts to actual frame timing. However, when
an application explicitly configures a bitrate target, the firmware must
follow that target regardless of frame timing.
Fix this by adding the TIME_DELTA_BASED_RC capability with a default value
of 0 (disabled) and sending HFI_PROP_TIME_DELTA_BASED_RATE_CONTROL = 0 to
the firmware during stream-on, allowing the firmware to use the configured
bitrate as the target.

Signed-off-by: Gourav Kumar <gouravk@qti.qualcomm.com>
Signed-off-by: Vishnu Reddy <busanna.reddy@oss.qualcomm.com>
Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
Signed-off-by: Bryan O'Donoghue <bod@kernel.org>
This commit is contained in:
Gourav Kumar 2026-07-10 08:24:04 +05:30 • committed by Bryan O'Donoghue
commit 6eec0f9b5c
5 changed files with 32 additions and 0 deletions
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