From: Arun Iyengar via B4 Relay <devnull+aiyengar1990.gmail.com@kernel.org>
To: Mauro Carvalho Chehab <mchehab@kernel.org>,
Paul Kocialkowski <paulk@sys-base.io>
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
Nicolas Dufresne <nicolas.dufresne@collabora.com>,
Hans Verkuil <hverkuil@kernel.org>,
Marco Felsch <m.felsch@pengutronix.de>,
Michael Tretter <m.tretter@pengutronix.de>,
Arun Iyengar <aiyengar1990@gmail.com>
Subject: [PATCH RFC 03/11] media: h264: Write the stateless encode SPS and PPS with nal_ref_idc 3
Date: Tue, 10 Nov 2026 10:05:17 +0000 [thread overview]
Message-ID: <20261110-h264-encode-fixes-v1-3-7a64486df499@gmail.com> (raw)
In-Reply-To: <20261110-h264-encode-fixes-v1-0-7a64486df499@gmail.com>
From: Arun Iyengar <aiyengar1990@gmail.com>
The sequence and picture parameter set NAL units are written with
nal_ref_idc 0, which ITU-T H.264 section 7.4.1 forbids: "nal_ref_idc
shall not be equal to 0 for sequence parameter set or sequence parameter
set extension or subset sequence parameter set or picture parameter set
NAL units". FFmpeg's H.264 probe rejects such streams (an Annex B file
from the encoder is "detected only with low score of 1"), and stricter
decoders may drop the parameter sets.
Write them with nal_ref_idc 3, as other encoders do. Access unit
delimiters keep 0, which the specification requires for them.
Signed-off-by: Arun Iyengar <aiyengar1990@gmail.com>
---
drivers/media/v4l2-core/v4l2-h264-enc-rbsp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-h264-enc-rbsp.c b/drivers/media/v4l2-core/v4l2-h264-enc-rbsp.c
index 2d751855195b..fa5857b77d76 100644
--- a/drivers/media/v4l2-core/v4l2-h264-enc-rbsp.c
+++ b/drivers/media/v4l2-core/v4l2-h264-enc-rbsp.c
@@ -654,7 +654,7 @@ int v4l2_h264_enc_rbsp_sps(struct v4l2_h264_enc_rbsp *rbsp,
unsigned int i;
int ret;
- ret = v4l2_h264_enc_rbsp_nalu_begin(rbsp, 0, V4L2_H264_NALU_TYPE_SPS);
+ ret = v4l2_h264_enc_rbsp_nalu_begin(rbsp, 3, V4L2_H264_NALU_TYPE_SPS);
if (ret)
return ret;
@@ -845,7 +845,7 @@ int v4l2_h264_enc_rbsp_pps(struct v4l2_h264_enc_rbsp *rbsp,
u8 pic_scaling_matrix_present_flag = 0;
int ret;
- ret = v4l2_h264_enc_rbsp_nalu_begin(rbsp, 0, V4L2_H264_NALU_TYPE_PPS);
+ ret = v4l2_h264_enc_rbsp_nalu_begin(rbsp, 3, V4L2_H264_NALU_TYPE_PPS);
if (ret)
return ret;
--
2.55.0
next prev parent reply other threads:[~2026-11-10 10:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-10 10:05 [PATCH RFC 00/11] media: h264: Stateless encode core follow-ups: parameter sets, POC type 2, CBR and VBR Arun Iyengar via B4 Relay
2026-11-10 10:05 ` [PATCH RFC 01/11] media: h264: Only write the SPS and PPS of a stateless encode when they change Arun Iyengar via B4 Relay
2026-11-10 10:05 ` [PATCH RFC 02/11] media: h264: Support picture order count type 2 in stateless encode Arun Iyengar via B4 Relay
2026-11-10 10:05 ` Arun Iyengar via B4 Relay [this message]
2026-11-10 10:05 ` [PATCH RFC 04/11] media: v4l2-h264-enc-rc: Rework the constant bitrate mode Arun Iyengar via B4 Relay
2026-11-10 10:05 ` [PATCH RFC 05/11] media: v4l2-core: Move the H.264 encode CBR rate control to a helper Arun Iyengar via B4 Relay
2026-11-10 10:05 ` [PATCH RFC 06/11] media: v4l2-core: Bound the I picture size in the encode CBR rate control Arun Iyengar via B4 Relay
2026-11-10 10:05 ` [PATCH RFC 07/11] media: v4l2-core: Halve the I picture QP increase of the encode CBR Arun Iyengar via B4 Relay
2026-11-10 10:05 ` [PATCH RFC 08/11] media: v4l2-core: Re-encode oversized pictures in " Arun Iyengar via B4 Relay
2026-11-10 10:05 ` [PATCH RFC 09/11] media: v4l2-core: Fix all-intra streams in the encode CBR rate control Arun Iyengar via B4 Relay
2026-11-10 10:05 ` [PATCH RFC 10/11] media: v4l2-core: Add a peak bitrate to the encode " Arun Iyengar via B4 Relay
2026-11-10 10:05 ` [PATCH RFC 11/11] media: h264: Add a VBR mode to the stateless " Arun Iyengar via B4 Relay
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