From 6eec0f9b5c31f92f2ad659af5984e89b722dfcfb Mon Sep 17 00:00:00 2001 From: Gourav Kumar Date: Fri, 10 Jul 2026 08:24:04 +0530 Subject: media: iris: disable time-delta-based rate control for VBR 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 Signed-off-by: Vishnu Reddy Reviewed-by: Vikash Garodia Signed-off-by: Bryan O'Donoghue --- drivers/media/platform/qcom/iris/iris_ctrls.c | 19 +++++++++++++++++++ drivers/media/platform/qcom/iris/iris_ctrls.h | 1 + drivers/media/platform/qcom/iris/iris_hfi_gen2.c | 10 ++++++++++ .../media/platform/qcom/iris/iris_hfi_gen2_defines.h | 1 + .../media/platform/qcom/iris/iris_platform_common.h | 1 + 5 files changed, 32 insertions(+) diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/media/platform/qcom/iris/iris_ctrls.c index 2918a7df0b40..bf17d310eac0 100644 --- a/drivers/media/platform/qcom/iris/iris_ctrls.c +++ b/drivers/media/platform/qcom/iris/iris_ctrls.c @@ -1499,6 +1499,25 @@ int iris_set_req_sync_frame(struct iris_inst *inst, enum platform_inst_fw_cap_ty &hfi_val, sizeof(u32)); } +int iris_set_time_delta_based_rc(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id) +{ + const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops; + u32 hfi_id = inst->fw_caps[cap_id].hfi_id; + u32 value = inst->fw_caps[cap_id].value; + + /* + * Disable time-delta-based rate control (value = 0). + * This overrides the firmware's default (enabled), ensuring the + * firmware uses the configured bitrate target rather than calculating + * bitrate from frame timing. + */ + return hfi_ops->session_set_property(inst, hfi_id, + HFI_HOST_FLAGS_NONE, + iris_get_port_info(inst, cap_id), + HFI_PAYLOAD_U32, + &value, sizeof(u32)); +} + int iris_set_properties(struct iris_inst *inst, u32 plane) { const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops; diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.h b/drivers/media/platform/qcom/iris/iris_ctrls.h index 8d8bbef96007..5180d53d3c90 100644 --- a/drivers/media/platform/qcom/iris/iris_ctrls.h +++ b/drivers/media/platform/qcom/iris/iris_ctrls.h @@ -48,6 +48,7 @@ int iris_set_layer_count_gen1(struct iris_inst *inst, enum platform_inst_fw_cap_ int iris_set_layer_count_gen2(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id); int iris_set_layer_bitrate(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id); int iris_set_req_sync_frame(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id); +int iris_set_time_delta_based_rc(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id); int iris_set_properties(struct iris_inst *inst, u32 plane); #endif diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c index 619a54edb09f..3b8fbefb8b93 100644 --- a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c +++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c @@ -1240,6 +1240,16 @@ static const struct platform_inst_fw_cap inst_fw_cap_sm8550_enc[] = { .flags = CAP_FLAG_OUTPUT_PORT | CAP_FLAG_MENU, .set = iris_set_bitrate_mode_gen2, }, + { + .cap_id = TIME_DELTA_BASED_RC, + .min = 0, + .max = 1, + .step_or_mask = 1, + .value = 0, + .hfi_id = HFI_PROP_TIME_DELTA_BASED_RATE_CONTROL, + .flags = CAP_FLAG_OUTPUT_PORT, + .set = iris_set_time_delta_based_rc, + }, { .cap_id = FRAME_SKIP_MODE, .min = V4L2_MPEG_VIDEO_FRAME_SKIP_MODE_DISABLED, diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h index a8b47e4ceba0..f43aea10090d 100644 --- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h +++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h @@ -67,6 +67,7 @@ enum hfi_rate_control { }; #define HFI_PROP_RATE_CONTROL 0x0300012a +#define HFI_PROP_TIME_DELTA_BASED_RATE_CONTROL 0x0300012b #define HFI_PROP_QP_PACKED 0x0300012e #define HFI_PROP_MIN_QP_PACKED 0x0300012f #define HFI_PROP_MAX_QP_PACKED 0x03000130 diff --git a/drivers/media/platform/qcom/iris/iris_platform_common.h b/drivers/media/platform/qcom/iris/iris_platform_common.h index d8481a9689d5..974809509146 100644 --- a/drivers/media/platform/qcom/iris/iris_platform_common.h +++ b/drivers/media/platform/qcom/iris/iris_platform_common.h @@ -185,6 +185,7 @@ enum platform_inst_fw_cap_type { LAYER4_BITRATE_HEVC, LAYER5_BITRATE_HEVC, REQUEST_SYNC_FRAME, + TIME_DELTA_BASED_RC, INST_FW_CAP_MAX, }; -- cgit v1.2.3