lavc: Add coded bitstream read/write support for H.264

(cherry picked from commit acf06f45)
(cherry picked from commit 768eb918)
(cherry picked from commit e7f64191)

configure

@@ -2151,6 +2151,7 @@ CONFIG_EXTRA="
     bswapdsp
     cabac
     cbs
+    cbs_h264
     dirac_parse
     dvprofile
     exif
@@ -2404,6 +2405,7 @@ w32threads_deps="atomics_native"
 threads_if_any="$THREADS_LIST"
 
 # subsystems
+cbs_h264_select="cbs golomb"
 dct_select="rdft"
 dirac_parse_select="golomb"
 error_resilience_select="me_cmp"

libavcodec/Makefile

@@ -60,6 +60,7 @@ OBJS-$(CONFIG_BLOCKDSP)                += blockdsp.o
 OBJS-$(CONFIG_BSWAPDSP)                += bswapdsp.o
 OBJS-$(CONFIG_CABAC)                   += cabac.o
 OBJS-$(CONFIG_CBS)                     += cbs.o
+OBJS-$(CONFIG_CBS_H264)                += cbs_h2645.o h2645_parse.o
 OBJS-$(CONFIG_CRYSTALHD)               += crystalhd.o
 OBJS-$(CONFIG_DCT)                     += dct.o dct32_fixed.o dct32_float.o
 OBJS-$(CONFIG_ERROR_RESILIENCE)        += error_resilience.o

libavcodec/cbs.c

@@ -28,6 +28,9 @@
 
 
 static const CodedBitstreamType *cbs_type_table[] = {
+#if CONFIG_CBS_H264
+    &ff_cbs_type_h264,
+#endif
 };
 
 int ff_cbs_init(CodedBitstreamContext **ctx_ptr,

libavcodec/cbs.h

@@ -42,6 +42,8 @@ struct CodedBitstreamType;
 
 /**
  * The codec-specific type of a bitstream unit.
+ *
+ * H.264 / AVC: nal_unit_type
  */
 typedef uint32_t CodedBitstreamUnitType;
 

libavcodec/cbs_h2645.h

+/*
+ * 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_H2645_H
+#define AVCODEC_CBS_H2645_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "h2645_parse.h"
+
+
+typedef struct CodedBitstreamH2645Context {
+    // If set, the stream being read is in MP4 (AVCC/HVCC) format.  If not
+    // set, the stream is assumed to be in annex B format.
+    int mp4;
+    // Size in bytes of the NAL length field for MP4 format.
+    int nal_length_size;
+    // Packet reader.
+    H2645Packet read_packet;
+
+    // Write buffer
+    uint8_t *write_buffer;
+    size_t write_buffer_size;
+} CodedBitstreamH2645Context;
+
+
+#endif /* AVCODEC_CBS_H2645_H */

libavcodec/cbs_internal.h

@@ -83,4 +83,7 @@ int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
                           uint32_t range_min, uint32_t range_max);
 
 
+extern const CodedBitstreamType ff_cbs_type_h264;
+
+
 #endif /* AVCODEC_CBS_INTERNAL_H */