[FFmpeg-devel] [PATCH] lavc/vaapi_encode: fix PoC negative issue

[Jun Zhao]

From e37b2598d372b790c0a496c7b750802a1aa102be Mon Sep 17 00:00:00 2001
From: Jun Zhao <jun.zhao at intel.com>
Date: Wed, 8 Feb 2017 15:25:18 +0800
Subject: [PATCH] lavc/vaapi_encode: fix PoC negative issue.

the issue occurs when setting a large b frames number with option "bf",
it results from hard coding the sps.log2_max_pic_order_cnt_lsb_minus4 with
0/8 in h264/hevc vaapi encoder.

Signed-off-by: Jun Zhao <jun.zhao at intel.com>
Signed-off-by: Yi A Wang <yi.a.wang at intel.com>
---
 libavcodec/vaapi_encode_h264.c | 7 +++++++
 libavcodec/vaapi_encode_h265.c | 7 ++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/libavcodec/vaapi_encode_h264.c b/libavcodec/vaapi_encode_h264.c
index 00d8e6a..946f8b9 100644
--- a/libavcodec/vaapi_encode_h264.c
+++ b/libavcodec/vaapi_encode_h264.c
@@ -784,6 +784,8 @@ static int vaapi_encode_h264_init_sequence_params(AVCodecContext *avctx)
     VAAPIEncodeH264Context            *priv = ctx->priv_data;
     VAAPIEncodeH264MiscSequenceParams *mseq = &priv->misc_sequence_params;
     int i;
+    int max_delta_poc;
+    int log2_max_poc_lsb = 4;
 
     {
         vseq->seq_parameter_set_id = 0;
@@ -801,6 +803,11 @@ static int vaapi_encode_h264_init_sequence_params(AVCodecContext *avctx)
         vseq->seq_fields.bits.log2_max_frame_num_minus4 = 4;
         vseq->seq_fields.bits.pic_order_cnt_type = 0;
 
+        max_delta_poc = (avctx->max_b_frames + 2) * 2;
+        while ((1 << log2_max_poc_lsb) <= max_delta_poc * 2)
+            log2_max_poc_lsb++;
+        vseq->seq_fields.bits.log2_max_pic_order_cnt_lsb_minus4 = log2_max_poc_lsb - 4;
+
         if (avctx->width  != ctx->surface_width ||
             avctx->height != ctx->surface_height) {
             vseq->frame_cropping_flag = 1;
diff --git a/libavcodec/vaapi_encode_h265.c b/libavcodec/vaapi_encode_h265.c
index c5589ed..2fb8a3f 100644
--- a/libavcodec/vaapi_encode_h265.c
+++ b/libavcodec/vaapi_encode_h265.c
@@ -786,6 +786,8 @@ static int vaapi_encode_h265_init_sequence_params(AVCodecContext *avctx)
     VAAPIEncodeH265Context            *priv = ctx->priv_data;
     VAAPIEncodeH265MiscSequenceParams *mseq = &priv->misc_sequence_params;
     int i;
+    int max_delta_poc;
+    int log2_max_poc_lsb = 8;
 
     {
         // general_profile_space == 0.
@@ -895,7 +897,10 @@ static int vaapi_encode_h265_init_sequence_params(AVCodecContext *avctx)
         mseq->general_frame_only_constraint_flag = 1;
         mseq->general_inbld_flag = 0;
 
-        mseq->log2_max_pic_order_cnt_lsb_minus4 = 8;
+        max_delta_poc = (avctx->max_b_frames + 2) * 2;
+        while ((1 << log2_max_poc_lsb) <= max_delta_poc)
+            log2_max_poc_lsb++;
+        mseq->log2_max_pic_order_cnt_lsb_minus4 = log2_max_poc_lsb - 4;
         mseq->vps_sub_layer_ordering_info_present_flag = 0;
         mseq->vps_max_dec_pic_buffering_minus1[0] = (avctx->max_b_frames > 0) + 1;
         mseq->vps_max_num_reorder_pics[0]         = (avctx->max_b_frames > 0);
-- 
2.9.3