hevc: split bitstream unescaping to a separate file

It will be useful in the QSV HEVC encoder.

4 files changed, 137 insertions, 103 deletions

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 2b6d65b60f..e04ee55b90 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -240,7 +240,7 @@ OBJS-$(CONFIG_HAP_DECODER)             += hapdec.o
 OBJS-$(CONFIG_HAP_ENCODER)             += hapenc.o
 OBJS-$(CONFIG_HEVC_DECODER)            += hevc.o hevc_mvs.o hevc_ps.o hevc_sei.o \
                                           hevc_cabac.o hevc_refs.o hevcpred.o    \
-                                          hevcdsp.o hevc_filter.o
+                                          hevcdsp.o hevc_filter.o hevc_parse.o
 OBJS-$(CONFIG_HEVC_NVENC_ENCODER)      += nvenc_hevc.o
 OBJS-$(CONFIG_HNM4_VIDEO_DECODER)      += hnm4video.o
 OBJS-$(CONFIG_HQ_HQA_DECODER)          += hq_hqa.o hq_hqadata.o hq_hqadsp.o \
diff --git a/libavcodec/hevc.c b/libavcodec/hevc.c
index 97014391f2..ce4533e639 100644
--- a/libavcodec/hevc.c
+++ b/libavcodec/hevc.c
@@ -2643,107 +2643,6 @@ fail:
     return 0;
 }
 
-/* FIXME: This is adapted from ff_h264_decode_nal, avoiding duplication
- * between these functions would be nice. */
-static int extract_rbsp(const uint8_t *src, int length,
-                        HEVCNAL *nal)
-{
-    int i, si, di;
-    uint8_t *dst;
-
-#define STARTCODE_TEST                                                  \
-        if (i + 2 < length && src[i + 1] == 0 && src[i + 2] <= 3) {     \
-            if (src[i + 2] != 3) {                                      \
-                /* startcode, so we must be past the end */             \
-                length = i;                                             \
-            }                                                           \
-            break;                                                      \
-        }
-#if HAVE_FAST_UNALIGNED
-#define FIND_FIRST_ZERO                                                 \
-        if (i > 0 && !src[i])                                           \
-            i--;                                                        \
-        while (src[i])                                                  \
-            i++
-#if HAVE_FAST_64BIT
-    for (i = 0; i + 1 < length; i += 9) {
-        if (!((~AV_RN64A(src + i) &
-               (AV_RN64A(src + i) - 0x0100010001000101ULL)) &
-              0x8000800080008080ULL))
-            continue;
-        FIND_FIRST_ZERO;
-        STARTCODE_TEST;
-        i -= 7;
-    }
-#else
-    for (i = 0; i + 1 < length; i += 5) {
-        if (!((~AV_RN32A(src + i) &
-               (AV_RN32A(src + i) - 0x01000101U)) &
-              0x80008080U))
-            continue;
-        FIND_FIRST_ZERO;
-        STARTCODE_TEST;
-        i -= 3;
-    }
-#endif /* HAVE_FAST_64BIT */
-#else
-    for (i = 0; i + 1 < length; i += 2) {
-        if (src[i])
-            continue;
-        if (i > 0 && src[i - 1] == 0)
-            i--;
-        STARTCODE_TEST;
-    }
-#endif /* HAVE_FAST_UNALIGNED */
-
-    if (i >= length - 1) { // no escaped 0
-        nal->data     =
-        nal->raw_data = src;
-        nal->size     =
-        nal->raw_size = length;
-        return length;
-    }
-
-    av_fast_malloc(&nal->rbsp_buffer, &nal->rbsp_buffer_size,
-                   length + FF_INPUT_BUFFER_PADDING_SIZE);
-    if (!nal->rbsp_buffer)
-        return AVERROR(ENOMEM);
-
-    dst = nal->rbsp_buffer;
-
-    memcpy(dst, src, i);
-    si = di = i;
-    while (si + 2 < length) {
-        // remove escapes (very rare 1:2^22)
-        if (src[si + 2] > 3) {
-            dst[di++] = src[si++];
-            dst[di++] = src[si++];
-        } else if (src[si] == 0 && src[si + 1] == 0) {
-            if (src[si + 2] == 3) { // escape
-                dst[di++] = 0;
-                dst[di++] = 0;
-                si       += 3;
-
-                continue;
-            } else // next start code
-                goto nsc;
-        }
-
-        dst[di++] = src[si++];
-    }
-    while (si < length)
-        dst[di++] = src[si++];
-
-nsc:
-    memset(dst + di, 0, FF_INPUT_BUFFER_PADDING_SIZE);
-
-    nal->data = dst;
-    nal->size = di;
-    nal->raw_data = src;
-    nal->raw_size = si;
-    return si;
-}
-
 static int decode_nal_units(HEVCContext *s, const uint8_t *buf, int length)
 {
     int i, consumed, ret = 0;
@@ -2800,7 +2699,7 @@ static int decode_nal_units(HEVCContext *s, const uint8_t *buf, int length)
         }
         nal = &s->nals[s->nb_nals++];
 
-        consumed = extract_rbsp(buf, extract_length, nal);
+        consumed = ff_hevc_extract_rbsp(buf, extract_length, nal);
         if (consumed < 0) {
             ret = consumed;
             goto fail;
diff --git a/libavcodec/hevc.h b/libavcodec/hevc.h
index 27b0af6b95..8b06e1f4cd 100644
--- a/libavcodec/hevc.h
+++ b/libavcodec/hevc.h
@@ -1002,6 +1002,12 @@ void ff_hevc_pps_free(HEVCPPS **ppps);
 
 void ff_hevc_pred_init(HEVCPredContext *hpc, int bit_depth);
 
+/**
+ * Extract the raw (unescaped) HEVC bitstream.
+ */
+int ff_hevc_extract_rbsp(const uint8_t *src, int length,
+                         HEVCNAL *nal);
+
 extern const uint8_t ff_hevc_qpel_extra_before[4];
 extern const uint8_t ff_hevc_qpel_extra_after[4];
 extern const uint8_t ff_hevc_qpel_extra[4];
diff --git a/libavcodec/hevc_parse.c b/libavcodec/hevc_parse.c
new file mode 100644
index 0000000000..32a440bf92
--- /dev/null
+++ b/libavcodec/hevc_parse.c
@@ -0,0 +1,129 @@
+/*
+ * HEVC common code
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <string.h>
+
+#include "config.h"
+
+#include "libavutil/intreadwrite.h"
+#include "libavutil/mem.h"
+
+#include "hevc.h"
+
+/* FIXME: This is adapted from ff_h264_decode_nal, avoiding duplication
+ * between these functions would be nice. */
+int ff_hevc_extract_rbsp(const uint8_t *src, int length,
+                         HEVCNAL *nal)
+{
+    int i, si, di;
+    uint8_t *dst;
+
+#define STARTCODE_TEST                                                  \
+        if (i + 2 < length && src[i + 1] == 0 && src[i + 2] <= 3) {     \
+            if (src[i + 2] != 3) {                                      \
+                /* startcode, so we must be past the end */             \
+                length = i;                                             \
+            }                                                           \
+            break;                                                      \
+        }
+#if HAVE_FAST_UNALIGNED
+#define FIND_FIRST_ZERO                                                 \
+        if (i > 0 && !src[i])                                           \
+            i--;                                                        \
+        while (src[i])                                                  \
+            i++
+#if HAVE_FAST_64BIT
+    for (i = 0; i + 1 < length; i += 9) {
+        if (!((~AV_RN64A(src + i) &
+               (AV_RN64A(src + i) - 0x0100010001000101ULL)) &
+              0x8000800080008080ULL))
+            continue;
+        FIND_FIRST_ZERO;
+        STARTCODE_TEST;
+        i -= 7;
+    }
+#else
+    for (i = 0; i + 1 < length; i += 5) {
+        if (!((~AV_RN32A(src + i) &
+               (AV_RN32A(src + i) - 0x01000101U)) &
+              0x80008080U))
+            continue;
+        FIND_FIRST_ZERO;
+        STARTCODE_TEST;
+        i -= 3;
+    }
+#endif /* HAVE_FAST_64BIT */
+#else
+    for (i = 0; i + 1 < length; i += 2) {
+        if (src[i])
+            continue;
+        if (i > 0 && src[i - 1] == 0)
+            i--;
+        STARTCODE_TEST;
+    }
+#endif /* HAVE_FAST_UNALIGNED */
+
+    if (i >= length - 1) { // no escaped 0
+        nal->data     =
+        nal->raw_data = src;
+        nal->size     =
+        nal->raw_size = length;
+        return length;
+    }
+
+    av_fast_malloc(&nal->rbsp_buffer, &nal->rbsp_buffer_size,
+                   length + FF_INPUT_BUFFER_PADDING_SIZE);
+    if (!nal->rbsp_buffer)
+        return AVERROR(ENOMEM);
+
+    dst = nal->rbsp_buffer;
+
+    memcpy(dst, src, i);
+    si = di = i;
+    while (si + 2 < length) {
+        // remove escapes (very rare 1:2^22)
+        if (src[si + 2] > 3) {
+            dst[di++] = src[si++];
+            dst[di++] = src[si++];
+        } else if (src[si] == 0 && src[si + 1] == 0) {
+            if (src[si + 2] == 3) { // escape
+                dst[di++] = 0;
+                dst[di++] = 0;
+                si       += 3;
+
+                continue;
+            } else // next start code
+                goto nsc;
+        }
+
+        dst[di++] = src[si++];
+    }
+    while (si < length)
+        dst[di++] = src[si++];
+
+nsc:
+    memset(dst + di, 0, FF_INPUT_BUFFER_PADDING_SIZE);
+
+    nal->data = dst;
+    nal->size = di;
+    nal->raw_data = src;
+    nal->raw_size = si;
+    return si;
+}