lavc: Add coded bitstream read/write API

(cherry picked from commit 18f1706f331bf5dd565774eae680508c8d3a97ad)
(cherry picked from commit 44cde38c8acbef7d5250e6d1b52b1020871e093b)

1 files changed, 86 insertions, 0 deletions

diff --git a/libavcodec/cbs_internal.h b/libavcodec/cbs_internal.h
new file mode 100644
index 0000000000..f6a42beea3
--- /dev/null
+++ b/libavcodec/cbs_internal.h
@@ -0,0 +1,86 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_CBS_INTERNAL_H
+#define AVCODEC_CBS_INTERNAL_H
+
+#include "avcodec.h"
+#include "cbs.h"
+#include "get_bits.h"
+#include "put_bits.h"
+
+
+typedef struct CodedBitstreamType {
+    enum AVCodecID codec_id;
+
+    size_t priv_data_size;
+
+    // Split frag->data into coded bitstream units, creating the
+    // frag->units array.  Fill data but not content on each unit.
+    // header is set if the fragment came from a header block, which
+    // may require different parsing for some codecs (e.g. the AVCC
+    // header in H.264).
+    int (*split_fragment)(CodedBitstreamContext *ctx,
+                          CodedBitstreamFragment *frag,
+                          int header);
+
+    // Read the unit->data bitstream and decompose it, creating
+    // unit->content.
+    int (*read_unit)(CodedBitstreamContext *ctx,
+                     CodedBitstreamUnit *unit);
+
+    // Write the unit->data bitstream from unit->content.
+    int (*write_unit)(CodedBitstreamContext *ctx,
+                      CodedBitstreamUnit *unit);
+
+    // Read the data from all of frag->units and assemble it into
+    // a bitstream for the whole fragment.
+    int (*assemble_fragment)(CodedBitstreamContext *ctx,
+                             CodedBitstreamFragment *frag);
+
+    // Free the content and data of a single unit.
+    void (*free_unit)(CodedBitstreamUnit *unit);
+
+    // Free the codec internal state.
+    void (*close)(CodedBitstreamContext *ctx);
+} CodedBitstreamType;
+
+
+// Helper functions for trace output.
+
+void ff_cbs_trace_header(CodedBitstreamContext *ctx,
+                         const char *name);
+
+void ff_cbs_trace_syntax_element(CodedBitstreamContext *ctx,
+                                 int position, const char *name,
+                                 const char *bitstring, int64_t value);
+
+
+// Helper functions for read/write of common bitstream elements, including
+// generation of trace output.
+
+int ff_cbs_read_unsigned(CodedBitstreamContext *ctx, GetBitContext *gbc,
+                         int width, const char *name, uint32_t *write_to,
+                         uint32_t range_min, uint32_t range_max);
+
+int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
+                          int width, const char *name, uint32_t value,
+                          uint32_t range_min, uint32_t range_max);
+
+
+#endif /* AVCODEC_CBS_INTERNAL_H */