[FFmpeg-devel] [FFmpeg-devel v10 4/9] Added demuxer to handle reading EVC video files
Dawid Kozinski
d.kozinski at samsung.com
Thu Aug 25 16:35:12 EEST 2022
- Provided AVInputFormat structure describing EVC input format (ff_evc_demuxer)
Signed-off-by: Dawid Kozinski <d.kozinski at samsung.com>
---
libavformat/Makefile | 1 +
libavformat/allformats.c | 1 +
libavformat/evcdec.c | 142 +++++++++++++++++++++++++++++++++++++++
3 files changed, 144 insertions(+)
create mode 100644 libavformat/evcdec.c
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 7e3f0e6794..a320cac22b 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -249,6 +249,7 @@ OBJS-$(CONFIG_HCOM_DEMUXER) += hcom.o pcm.o
OBJS-$(CONFIG_HDS_MUXER) += hdsenc.o
OBJS-$(CONFIG_HEVC_DEMUXER) += hevcdec.o rawdec.o
OBJS-$(CONFIG_HEVC_MUXER) += rawenc.o
+OBJS-$(CONFIG_EVC_DEMUXER) += evcdec.o rawdec.o
OBJS-$(CONFIG_EVC_MUXER) += rawenc.o
OBJS-$(CONFIG_HLS_DEMUXER) += hls.o hls_sample_encryption.o
OBJS-$(CONFIG_HLS_MUXER) += hlsenc.o hlsplaylist.o avc.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 31508b69f0..dfce49d149 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -148,6 +148,7 @@ extern const AVInputFormat ff_ea_cdata_demuxer;
extern const AVInputFormat ff_eac3_demuxer;
extern const AVOutputFormat ff_eac3_muxer;
extern const AVInputFormat ff_epaf_demuxer;
+extern const AVInputFormat ff_evc_demuxer;
extern const AVOutputFormat ff_evc_muxer;
extern const AVOutputFormat ff_f4v_muxer;
extern const AVInputFormat ff_ffmetadata_demuxer;
diff --git a/libavformat/evcdec.c b/libavformat/evcdec.c
new file mode 100644
index 0000000000..58dc671d24
--- /dev/null
+++ b/libavformat/evcdec.c
@@ -0,0 +1,142 @@
+/*
+ * RAW EVC video demuxer
+ *
+ * Copyright (c) 2021 Dawid Kozinski <d.kozinski at samsung.com>
+ *
+ * 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
+ */
+
+#include "libavcodec/get_bits.h"
+#include "libavcodec/golomb.h"
+#include "libavcodec/internal.h"
+
+#include "rawdec.h"
+#include "avformat.h"
+
+// The length field that indicates the length in bytes of the following NAL unit is configured to be of 4 bytes
+#define EVC_NAL_UNIT_LENGTH_BYTE (4) /* byte */
+
+#define EVC_NAL_HEADER_SIZE (2) /* byte */
+#define MAX_SPS_CNT (16) /* defined value in EVC standard */
+
+// NALU types
+// @see ISO_IEC_23094-1_2020 7.4.2.2 NAL unit header semantics
+//
+#define EVC_NUT_NONIDR (0) /* Coded slice of a non-IDR picture */
+#define EVC_NUT_IDR (1) /* Coded slice of an IDR picture */
+#define EVC_NUT_SPS (24) /* Sequence parameter set */
+#define EVC_NUT_PPS (25) /* Picture paremeter set */
+#define EVC_NUT_APS (26) /* Adaptation parameter set */
+#define EVC_NUT_FD (27) /* Filler data */
+#define EVC_NUT_SEI (28) /* Supplemental enhancement information */
+
+typedef struct EVCParserContext {
+ int got_sps;
+ int got_pps;
+ int got_idr;
+ int got_nonidr;
+} EVCParserContext;
+
+static int get_nalu_type(const uint8_t *bits, int bits_size)
+{
+ int unit_type_plus1 = 0;
+
+ if(bits_size >= EVC_NAL_HEADER_SIZE) {
+ unsigned char *p = (unsigned char *)bits;
+ // forbidden_zero_bit
+ if ((p[0] & 0x80) != 0) {
+ av_log(NULL, AV_LOG_ERROR, "Cannot get bitstream information. Malformed bitstream.\n");
+ return -1;
+ }
+
+ // nal_unit_type
+ unit_type_plus1 = (p[0] >> 1) & 0x3F;
+ }
+
+ return unit_type_plus1 - 1;
+}
+
+static uint32_t read_nal_unit_length(const uint8_t *bits, int bits_size)
+{
+ uint32_t nalu_len = 0;
+
+ if(bits_size >= EVC_NAL_UNIT_LENGTH_BYTE) {
+
+ int t = 0;
+ unsigned char *p = (unsigned char *)bits;
+
+ for(int i=0; i<EVC_NAL_UNIT_LENGTH_BYTE; i++) {
+ t = (t << 8) | p[i];
+ }
+
+ nalu_len = t;
+ if(nalu_len == 0) {
+ av_log(NULL, AV_LOG_ERROR, "Invalid bitstream size!\n");
+ return 0;
+ }
+ }
+
+ return nalu_len;
+}
+
+static int parse_nal_units(const AVProbeData *p, EVCParserContext *ev)
+{
+ int nalu_type;
+ size_t nalu_size;
+ unsigned char *bits = (unsigned char *)p->buf;
+ int bytes_to_read = p->buf_size;
+
+ while(bytes_to_read > EVC_NAL_UNIT_LENGTH_BYTE) {
+
+ nalu_size = read_nal_unit_length(bits, EVC_NAL_UNIT_LENGTH_BYTE);
+ if(nalu_size == 0) break;
+
+ bits += EVC_NAL_UNIT_LENGTH_BYTE;
+ bytes_to_read -= EVC_NAL_UNIT_LENGTH_BYTE;
+
+ if(bytes_to_read < nalu_size) break;
+
+ nalu_type = get_nalu_type(bits, bytes_to_read);
+
+ bits += nalu_size;
+ bytes_to_read -= nalu_size;
+
+ if (nalu_type == EVC_NUT_SPS)
+ ev->got_sps++;
+ else if (nalu_type == EVC_NUT_PPS)
+ ev->got_pps++;
+ else if (nalu_type == EVC_NUT_IDR )
+ ev->got_idr++;
+ else if (nalu_type == EVC_NUT_NONIDR)
+ ev->got_nonidr++;
+ }
+
+ return 0;
+}
+
+static int evc_probe(const AVProbeData *p)
+{
+ EVCParserContext ev = {0};
+ int ret = parse_nal_units(p, &ev);
+
+ if (ret == 0 && ev.got_sps && ev.got_pps && (ev.got_idr || ev.got_nonidr > 3))
+ return AVPROBE_SCORE_EXTENSION + 1; // 1 more than .mpg
+
+ return 0;
+}
+
+FF_DEF_RAWVIDEO_DEMUXER(evc, "raw EVC video", evc_probe, "evc", AV_CODEC_ID_EVC)
--
2.17.1
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