[Libva] [PATCH Libva-intel-driver V2 1/6] H264_Encoding: Parse the packed header data from user to fix the hacked code of HW skip bytes

[Zhao, Yakui]

From: "Zhao, Yakui" <yakui.zhao at intel.com>

When the packed header data from user is inserted into the coded clip, it uses
the hacked code to check the number of HW skip emulation bytes. This is wrong.
So fix it.
Of course if the packed header data is generated by the driver, it is
unnecessary to check it and it can still use the pre-defined number of HW
skip bytes.

V1->V2: Based on Gwenole's comment another nal_unit_type is added.

Signed-off-by: Zhao Yakui <yakui.zhao at intel.com>
---
 src/gen6_mfc_common.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 60 insertions(+), 3 deletions(-)

diff --git a/src/gen6_mfc_common.c b/src/gen6_mfc_common.c
index 33b9d55..7d52fc6 100644
--- a/src/gen6_mfc_common.c
+++ b/src/gen6_mfc_common.c
@@ -405,6 +405,58 @@ void intel_mfc_brc_prepare(struct encode_state *encode_state,
     }
 }
 
+static int intel_avc_find_skipemulcnt(unsigned char *buf, int bits_length)
+{
+    int i, found;
+    int leading_zero_cnt, byte_length, zero_byte;
+    int nal_unit_type;
+    int skip_cnt = 0;
+
+#define NAL_UNIT_TYPE_MASK 0x1f
+#define HW_MAX_SKIP_LENGTH 15
+
+    byte_length = ALIGN(bits_length, 32) >> 3;
+
+
+    leading_zero_cnt = 0;
+    found = 0;
+    for(i = 0; i < byte_length - 4; i++) {
+        if (((buf[i] == 0) && (buf[i + 1] == 0) && (buf[i + 2] == 1)) ||
+            ((buf[i] == 0) && (buf[i + 1] == 0) && (buf[i + 2] == 0) && (buf[i + 3] == 1))) {
+                found = 1;
+                break;
+            }
+        leading_zero_cnt++;
+    }
+    if (!found) {
+        /* warning message is complained. But anyway it will be inserted. */
+        WARN_ONCE("Invalid packed header data. "
+                   "Can't find the 000001 start_prefix code\n");
+        return 0;
+    }
+    i = leading_zero_cnt;
+
+    zero_byte = 0;
+    if (!((buf[i] == 0) && (buf[i + 1] == 0) && (buf[i + 2] == 1)))
+        zero_byte = 1;
+
+    skip_cnt = leading_zero_cnt + zero_byte + 3;
+
+    /* the unit header byte is accounted */
+    nal_unit_type = (buf[skip_cnt]) & NAL_UNIT_TYPE_MASK;
+    skip_cnt += 1;
+
+    if (nal_unit_type == 14 || nal_unit_type == 20 || nal_unit_type == 21) {
+        /* more unit header bytes are accounted for MVC/SVC */
+        skip_cnt += 3;
+    }
+    if (skip_cnt > HW_MAX_SKIP_LENGTH) {
+        WARN_ONCE("Too many leading zeros are padded for packed data. "
+                   "It is beyond the HW range.!!!\n");
+    }
+    return skip_cnt;
+}
+
 void intel_mfc_avc_pipeline_header_programing(VADriverContextP ctx,
                                               struct encode_state *encode_state,
                                               struct intel_encoder_context *encoder_context,
@@ -413,6 +465,7 @@ void intel_mfc_avc_pipeline_header_programing(VADriverContextP ctx,
     struct gen6_mfc_context *mfc_context = encoder_context->mfc_context;
     int idx = va_enc_packed_type_to_idx(VAEncPackedHeaderH264_SPS);
     unsigned int rate_control_mode = encoder_context->rate_control_mode;
+    unsigned int skip_emul_byte_cnt;
 
     if (encode_state->packed_header_data[idx]) {
         VAEncPackedHeaderParameterBuffer *param = NULL;
@@ -423,12 +476,13 @@ void intel_mfc_avc_pipeline_header_programing(VADriverContextP ctx,
         param = (VAEncPackedHeaderParameterBuffer *)encode_state->packed_header_param[idx]->buffer;
         length_in_bits = param->bit_length;
 
+        skip_emul_byte_cnt = intel_avc_find_skipemulcnt((unsigned char *)header_data, length_in_bits);
         mfc_context->insert_object(ctx,
                                    encoder_context,
                                    header_data,
                                    ALIGN(length_in_bits, 32) >> 5,
                                    length_in_bits & 0x1f,
-                                   5,   /* FIXME: check it */
+                                   skip_emul_byte_cnt,
                                    0,
                                    0,
                                    !param->has_emulation_bytes,
@@ -446,12 +500,14 @@ void intel_mfc_avc_pipeline_header_programing(VADriverContextP ctx,
         param = (VAEncPackedHeaderParameterBuffer *)encode_state->packed_header_param[idx]->buffer;
         length_in_bits = param->bit_length;
 
+        skip_emul_byte_cnt = intel_avc_find_skipemulcnt((unsigned char *)header_data, length_in_bits);
+
         mfc_context->insert_object(ctx,
                                    encoder_context,
                                    header_data,
                                    ALIGN(length_in_bits, 32) >> 5,
                                    length_in_bits & 0x1f,
-                                   5, /* FIXME: check it */
+                                   skip_emul_byte_cnt,
                                    0,
                                    0,
                                    !param->has_emulation_bytes,
@@ -469,12 +525,13 @@ void intel_mfc_avc_pipeline_header_programing(VADriverContextP ctx,
         param = (VAEncPackedHeaderParameterBuffer *)encode_state->packed_header_param[idx]->buffer;
         length_in_bits = param->bit_length;
 
+        skip_emul_byte_cnt = intel_avc_find_skipemulcnt((unsigned char *)header_data, length_in_bits);
         mfc_context->insert_object(ctx,
                                    encoder_context,
                                    header_data,
                                    ALIGN(length_in_bits, 32) >> 5,
                                    length_in_bits & 0x1f,
-                                   5, /* FIXME: check it */
+                                   skip_emul_byte_cnt,
                                    0,
                                    0,
                                    !param->has_emulation_bytes,
-- 
1.7.12-rc1