From 166924427ea0cd01c28975cefedc1b5aa1949c7d Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Fri, 11 Aug 2023 22:17:38 -0500
Subject: [PATCH] Use existing H.264 SPS as a template rather than building it
from scratch
---
src/cbs.cpp | 136 +++++++++++++++-------------------------------------
1 file changed, 38 insertions(+), 98 deletions(-)
diff --git a/src/cbs.cpp b/src/cbs.cpp
index c1d9df60..c1578825 100644
--- a/src/cbs.cpp
+++ b/src/cbs.cpp
@@ -87,92 +87,61 @@ namespace cbs {
return write(cbs_ctx, nal, uh, codec_id);
}
- util::buffer_t<std::uint8_t>
- make_sps_h264(const AVCodecContext *ctx) {
- H264RawSPS sps {};
-
- // b_per_p == ctx->max_b_frames for h264
- // desired_b_depth == avoption("b_depth") == 1
- // max_b_depth == std::min(av_log2(ctx->b_per_p) + 1, desired_b_depth) ==> 1
- auto max_b_depth = 1;
- auto dpb_frame = ctx->gop_size == 1 ? 0 : 1 + max_b_depth;
- auto mb_width = (FFALIGN(ctx->width, 16) / 16) * 16;
- auto mb_height = (FFALIGN(ctx->height, 16) / 16) * 16;
-
- sps.nal_unit_header.nal_ref_idc = 3;
- sps.nal_unit_header.nal_unit_type = H264_NAL_SPS;
-
- sps.profile_idc = FF_PROFILE_H264_HIGH & 0xFF;
-
- sps.constraint_set1_flag = 1;
-
- if (ctx->level != FF_LEVEL_UNKNOWN) {
- sps.level_idc = ctx->level;
- }
- else {
- auto framerate = ctx->framerate;
-
- auto level = ff_h264_guess_level(
- sps.profile_idc,
- ctx->bit_rate,
- framerate.num / framerate.den,
- mb_width,
- mb_height,
- dpb_frame);
-
- if (!level) {
- BOOST_LOG(error) << "Could not guess h264 level"sv;
-
- return {};
- }
- sps.level_idc = level->level_idc;
+ h264_t
+ make_sps_h264(const AVCodecContext *avctx, const AVPacket *packet) {
+ cbs::ctx_t ctx;
+ if (ff_cbs_init(&ctx, AV_CODEC_ID_H264, nullptr)) {
+ return {};
}
- sps.seq_parameter_set_id = 0;
- sps.chroma_format_idc = 1;
+ cbs::frag_t frag;
- sps.log2_max_frame_num_minus4 = 3; // 4;
- sps.pic_order_cnt_type = 0;
- sps.log2_max_pic_order_cnt_lsb_minus4 = 0; // 4;
+ int err = ff_cbs_read_packet(ctx.get(), &frag, &*packet);
+ if (err < 0) {
+ char err_str[AV_ERROR_MAX_STRING_SIZE] { 0 };
+ BOOST_LOG(error) << "Couldn't read packet: "sv << av_make_error_string(err_str, AV_ERROR_MAX_STRING_SIZE, err);
- sps.max_num_ref_frames = dpb_frame;
-
- sps.pic_width_in_mbs_minus1 = mb_width / 16 - 1;
- sps.pic_height_in_map_units_minus1 = mb_height / 16 - 1;
-
- sps.frame_mbs_only_flag = 1;
- sps.direct_8x8_inference_flag = 1;
-
- if (ctx->width != mb_width || ctx->height != mb_height) {
- sps.frame_cropping_flag = 1;
- sps.frame_crop_left_offset = 0;
- sps.frame_crop_top_offset = 0;
- sps.frame_crop_right_offset = (mb_width - ctx->width) / 2;
- sps.frame_crop_bottom_offset = (mb_height - ctx->height) / 2;
+ return {};
}
- sps.vui_parameters_present_flag = 1;
+ auto sps_p = ((CodedBitstreamH264Context *) ctx->priv_data)->active_sps;
- auto &vui = sps.vui;
+ // This is a very large struct that cannot safely be stored on the stack
+ auto sps = std::make_unique<H264RawSPS>(*sps_p);
+
+ if (avctx->refs > 0) {
+ sps->max_num_ref_frames = avctx->refs;
+ }
+
+ sps->vui_parameters_present_flag = 1;
+
+ auto &vui = sps->vui;
+ std::memset(&vui, 0, sizeof(vui));
vui.video_format = 5;
vui.colour_description_present_flag = 1;
vui.video_signal_type_present_flag = 1;
- vui.video_full_range_flag = ctx->color_range == AVCOL_RANGE_JPEG;
- vui.colour_primaries = ctx->color_primaries;
- vui.transfer_characteristics = ctx->color_trc;
- vui.matrix_coefficients = ctx->colorspace;
+ vui.video_full_range_flag = avctx->color_range == AVCOL_RANGE_JPEG;
+ vui.colour_primaries = avctx->color_primaries;
+ vui.transfer_characteristics = avctx->color_trc;
+ vui.matrix_coefficients = avctx->colorspace;
vui.low_delay_hrd_flag = 1 - vui.fixed_frame_rate_flag;
vui.bitstream_restriction_flag = 1;
vui.motion_vectors_over_pic_boundaries_flag = 1;
- vui.log2_max_mv_length_horizontal = 15;
- vui.log2_max_mv_length_vertical = 15;
- vui.max_num_reorder_frames = max_b_depth;
- vui.max_dec_frame_buffering = max_b_depth + 1;
+ vui.log2_max_mv_length_horizontal = 16;
+ vui.log2_max_mv_length_vertical = 16;
+ vui.max_num_reorder_frames = 0;
+ vui.max_dec_frame_buffering = sps->max_num_ref_frames;
- return write(sps.nal_unit_header.nal_unit_type, (void *) &sps.nal_unit_header, AV_CODEC_ID_H264);
+ cbs::ctx_t write_ctx;
+ ff_cbs_init(&write_ctx, AV_CODEC_ID_H264, nullptr);
+
+ return h264_t {
+ write(write_ctx, sps->nal_unit_header.nal_unit_type, (void *) &sps->nal_unit_header, AV_CODEC_ID_H264),
+ write(ctx, sps_p->nal_unit_header.nal_unit_type, (void *) &sps_p->nal_unit_header, AV_CODEC_ID_H264)
+ };
}
hevc_t
@@ -248,35 +217,6 @@ namespace cbs {
};
}
- util::buffer_t<std::uint8_t>
- read_sps_h264(const AVPacket *packet) {
- cbs::ctx_t ctx;
- if (ff_cbs_init(&ctx, AV_CODEC_ID_H264, nullptr)) {
- return {};
- }
-
- cbs::frag_t frag;
-
- int err = ff_cbs_read_packet(ctx.get(), &frag, &*packet);
- if (err < 0) {
- char err_str[AV_ERROR_MAX_STRING_SIZE] { 0 };
- BOOST_LOG(error) << "Couldn't read packet: "sv << av_make_error_string(err_str, AV_ERROR_MAX_STRING_SIZE, err);
-
- return {};
- }
-
- auto h264 = (H264RawNALUnitHeader *) ((CodedBitstreamH264Context *) ctx->priv_data)->active_sps;
- return write(h264->nal_unit_type, (void *) h264, AV_CODEC_ID_H264);
- }
-
- h264_t
- make_sps_h264(const AVCodecContext *ctx, const AVPacket *packet) {
- return h264_t {
- make_sps_h264(ctx),
- read_sps_h264(packet),
- };
- }
-
bool
validate_sps(const AVPacket *packet, int codec_id) {
cbs::ctx_t ctx;