[FFmpeg-devel] [PATCH] avcodec: add truehd_core bitstream filter
Paul B Mahol
onemda at gmail.com
Wed Nov 21 11:35:30 EET 2018
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
configure | 1 +
doc/bitstream_filters.texi | 4 +
libavcodec/Makefile | 1 +
libavcodec/bitstream_filters.c | 1 +
libavcodec/truehd_core_bsf.c | 184 +++++++++++++++++++++++++++++++++
5 files changed, 191 insertions(+)
create mode 100644 libavcodec/truehd_core_bsf.c
diff --git a/configure b/configure
index b4f944cfb0..faea24347e 100755
--- a/configure
+++ b/configure
@@ -3046,6 +3046,7 @@ hevc_metadata_bsf_select="cbs_h265"
mjpeg2jpeg_bsf_select="jpegtables"
mpeg2_metadata_bsf_select="cbs_mpeg2"
trace_headers_bsf_select="cbs"
+truehd_core_bsf_select="mlp_parser"
vp9_metadata_bsf_select="cbs_vp9"
# external libraries
diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
index 655a2c1e63..15c578aa8a 100644
--- a/doc/bitstream_filters.texi
+++ b/doc/bitstream_filters.texi
@@ -634,6 +634,10 @@ This can be useful for debugging low-level stream issues.
Supports H.264, H.265, MPEG-2 and VP9.
+ at section truehd_core
+
+Extract the core from a TrueHD stream, dropping ATMOS data.
+
@section vp9_metadata
Modify metadata embedded in a VP9 stream.
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 716f26d191..2840a8069f 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -1085,6 +1085,7 @@ OBJS-$(CONFIG_PRORES_METADATA_BSF) += prores_metadata_bsf.o
OBJS-$(CONFIG_REMOVE_EXTRADATA_BSF) += remove_extradata_bsf.o
OBJS-$(CONFIG_TEXT2MOVSUB_BSF) += movsub_bsf.o
OBJS-$(CONFIG_TRACE_HEADERS_BSF) += trace_headers_bsf.o
+OBJS-$(CONFIG_TRUEHD_CORE_BSF) += truehd_core_bsf.o mlp_parser.o mlp.o
OBJS-$(CONFIG_VP9_METADATA_BSF) += vp9_metadata_bsf.o
OBJS-$(CONFIG_VP9_RAW_REORDER_BSF) += vp9_raw_reorder_bsf.o
OBJS-$(CONFIG_VP9_SUPERFRAME_BSF) += vp9_superframe_bsf.o
diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
index 2a8598bac2..2c999d3c1d 100644
--- a/libavcodec/bitstream_filters.c
+++ b/libavcodec/bitstream_filters.c
@@ -51,6 +51,7 @@ extern const AVBitStreamFilter ff_prores_metadata_bsf;
extern const AVBitStreamFilter ff_remove_extradata_bsf;
extern const AVBitStreamFilter ff_text2movsub_bsf;
extern const AVBitStreamFilter ff_trace_headers_bsf;
+extern const AVBitStreamFilter ff_truehd_core_bsf;
extern const AVBitStreamFilter ff_vp9_metadata_bsf;
extern const AVBitStreamFilter ff_vp9_raw_reorder_bsf;
extern const AVBitStreamFilter ff_vp9_superframe_bsf;
diff --git a/libavcodec/truehd_core_bsf.c b/libavcodec/truehd_core_bsf.c
new file mode 100644
index 0000000000..be021af8e8
--- /dev/null
+++ b/libavcodec/truehd_core_bsf.c
@@ -0,0 +1,184 @@
+/*
+ * Copyright (c) 2018 Paul B Mahol
+ *
+ * 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 "avcodec.h"
+#include "bsf.h"
+#include "get_bits.h"
+#include "mlp_parser.h"
+#include "mlp.h"
+
+typedef struct AccessUnit {
+ uint8_t bits[4];
+ uint16_t offset;
+ uint16_t optional;
+} AccessUnit;
+
+typedef struct TrueHDCoreContext {
+ const AVClass *class;
+
+ MLPHeaderInfo hdr;
+} TrueHDCoreContext;
+
+static int truehd_core_filter(AVBSFContext *ctx, AVPacket *out)
+{
+ TrueHDCoreContext *s = ctx->priv_data;
+ GetBitContext gbc;
+ AccessUnit units[MAX_SUBSTREAMS];
+ AVPacket *in;
+ int ret, i, size, last_offset = 0;
+ int in_size, out_size;
+ int have_header = 0;
+ int substream_bits = 0;
+ int start, end;
+ uint16_t dts;
+
+ ret = ff_bsf_get_packet(ctx, &in);
+ if (ret < 0)
+ return ret;
+
+ if (in->size < 4)
+ goto fail;
+
+ ret = init_get_bits(&gbc, in->data, 32);
+ if (ret < 0)
+ goto fail;
+
+ skip_bits(&gbc, 4);
+ in_size = get_bits(&gbc, 12) * 2;
+ if (in_size < 4 || in_size > in->size)
+ goto fail;
+
+ out_size = in_size;
+ dts = get_bits(&gbc, 16);
+
+ ret = init_get_bits8(&gbc, in->data + 4, in->size - 4);
+ if (ret < 0)
+ goto fail;
+
+ if (show_bits_long(&gbc, 32) == 0xf8726fba) {
+ if ((ret = ff_mlp_read_major_sync(ctx, &s->hdr, &gbc)) != 0)
+ goto fail;
+ have_header = 1;
+ }
+
+ if (s->hdr.num_substreams > MAX_SUBSTREAMS)
+ goto fail;
+
+ start = get_bits_count(&gbc);
+ for (i = 0; i < s->hdr.num_substreams; i++) {
+ for (int j = 0; j < 4; j++)
+ units[i].bits[j] = get_bits1(&gbc);
+
+ units[i].offset = get_bits(&gbc, 12) * 2;
+ if (i < FFMIN(s->hdr.num_substreams, 3)) {
+ last_offset = units[i].offset;
+ substream_bits += 16;
+ }
+
+ if (units[i].bits[0]) {
+ units[i].optional = get_bits(&gbc, 16);
+ if (i < FFMIN(s->hdr.num_substreams, 3))
+ substream_bits += 16;
+ }
+ }
+ end = get_bits_count(&gbc);
+
+ size = ((end + 7) >> 3) + 4 + last_offset;
+ if (size >= 0 && size <= in->size)
+ out_size = size;
+ if (out_size < in_size) {
+ int bpos = 0, reduce = (end - start - substream_bits) >> 4;
+ uint16_t parity_nibble = 0;
+ uint16_t auheader;
+
+ ret = av_new_packet(out, out_size);
+ if (ret < 0)
+ goto fail;
+
+ AV_WB16(out->data + 2, dts);
+ parity_nibble = dts;
+ out->size -= reduce * 2;
+ parity_nibble ^= out->size / 2;
+
+ if (have_header) {
+ memcpy(out->data + 4, in->data + 4, 28);
+ out->data[16 + 4] = (out->data[16 + 4] & 0x0f) | (FFMIN(s->hdr.num_substreams, 3) << 4);
+ out->data[25 + 4] = out->data[25 + 4] & 0xfe;
+ out->data[26 + 4] = 0xff;
+ out->data[27 + 4] = 0xff;
+ AV_WL16(out->data + 4 + 26, ff_mlp_checksum16(out->data + 4, 26));
+ }
+
+ for (i = 0; i < FFMIN(s->hdr.num_substreams, 3); i++) {
+ uint16_t substr_hdr = 0;
+
+ substr_hdr |= (units[i].bits[0] << 15);
+ substr_hdr |= (units[i].bits[1] << 14);
+ substr_hdr |= (units[i].bits[2] << 13);
+ substr_hdr |= (units[i].bits[3] << 12);
+ substr_hdr |= (units[i].offset / 2) & 0x0FFF;
+
+ AV_WB16(out->data + have_header * 28 + 4 + bpos, substr_hdr);
+
+ parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
+ parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
+
+ if (units[i].bits[0]) {
+ AV_WB16(out->data + have_header * 28 + 4 + bpos, units[i].optional);
+
+ parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
+ parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
+ }
+ }
+
+ parity_nibble ^= parity_nibble >> 8;
+ parity_nibble ^= parity_nibble >> 4;
+ parity_nibble &= 0xF;
+
+ memcpy(out->data + have_header * 28 + 4 + bpos,
+ in->data + 4 + (end >> 3),
+ out_size - (4 + (end >> 3)));
+ auheader = (parity_nibble ^ 0xF) << 12;
+ auheader |= (out->size / 2) & 0x0fff;
+ AV_WB16(out->data, auheader);
+
+ ret = av_packet_copy_props(out, in);
+ } else {
+ av_packet_move_ref(out, in);
+ }
+
+fail:
+ if (ret < 0)
+ av_packet_unref(out);
+ av_packet_free(&in);
+
+ return ret;
+}
+
+static const enum AVCodecID codec_ids[] = {
+ AV_CODEC_ID_TRUEHD, AV_CODEC_ID_NONE,
+};
+
+const AVBitStreamFilter ff_truehd_core_bsf = {
+ .name = "truehd_core",
+ .priv_data_size = sizeof(TrueHDCoreContext),
+ .filter = truehd_core_filter,
+ .codec_ids = codec_ids,
+};
--
2.17.1
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