[FFmpeg-cvslog] lavc: add a bitstream filter for splitting VP9 superframes
Anton Khirnov
git at videolan.org
Sun Apr 23 05:28:07 EEST 2017
ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Sun Nov 13 11:00:02 2016 +0100| [03a80925effc2698d21dc0b00290eecf42dd9e68] | committer: Anton Khirnov
lavc: add a bitstream filter for splitting VP9 superframes
Partially based on code by Ronald S. Bultje <rsbultje at gmail.com>.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=03a80925effc2698d21dc0b00290eecf42dd9e68
---
doc/bitstream_filters.texi | 4 +
libavcodec/Makefile | 1 +
libavcodec/bitstream_filters.c | 1 +
libavcodec/vp9_superframe_split_bsf.c | 146 ++++++++++++++++++++++++++++++++++
4 files changed, 152 insertions(+)
diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
index 2e13cbe180..49b8a645d0 100644
--- a/doc/bitstream_filters.texi
+++ b/doc/bitstream_filters.texi
@@ -95,4 +95,8 @@ This bitstream filter passes the packets through unchanged.
@section remove_extradata
+ at section vp9_superframe_split
+
+Split VP9 superframes into single frames.
+
@c man end BITSTREAM FILTERS
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index d571d8def3..f07253a84d 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -767,6 +767,7 @@ OBJS-$(CONFIG_NOISE_BSF) += noise_bsf.o
OBJS-$(CONFIG_NULL_BSF) += null_bsf.o
OBJS-$(CONFIG_REMOVE_EXTRADATA_BSF) += remove_extradata_bsf.o
OBJS-$(CONFIG_TEXT2MOVSUB_BSF) += movsub_bsf.o
+OBJS-$(CONFIG_VP9_SUPERFRAME_SPLIT_BSF) += vp9_superframe_split_bsf.o
# thread libraries
OBJS-$(HAVE_LIBC_MSVCRT) += file_open.o
diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
index ee9e4bade5..1cea6d77af 100644
--- a/libavcodec/bitstream_filters.c
+++ b/libavcodec/bitstream_filters.c
@@ -38,6 +38,7 @@ extern const AVBitStreamFilter ff_null_bsf;
extern const AVBitStreamFilter ff_text2movsub_bsf;
extern const AVBitStreamFilter ff_noise_bsf;
extern const AVBitStreamFilter ff_remove_extradata_bsf;
+extern const AVBitStreamFilter ff_vp9_superframe_split_bsf;
#include "libavcodec/bsf_list.c"
diff --git a/libavcodec/vp9_superframe_split_bsf.c b/libavcodec/vp9_superframe_split_bsf.c
new file mode 100644
index 0000000000..4e635a3070
--- /dev/null
+++ b/libavcodec/vp9_superframe_split_bsf.c
@@ -0,0 +1,146 @@
+/*
+ * 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
+ */
+
+/**
+ * @file
+ * This bitstream filter splits VP9 superframes into packets containing
+ * just one frame.
+ */
+
+#include <stddef.h>
+
+#include "avcodec.h"
+#include "bsf.h"
+#include "bitstream.h"
+#include "bytestream.h"
+
+typedef struct VP9SFSplitContext {
+ AVPacket *buffer_pkt;
+
+ int nb_frames;
+ int next_frame;
+ size_t next_frame_offset;
+ int sizes[8];
+} VP9SFSplitContext;
+
+static int vp9_superframe_split_filter(AVBSFContext *ctx, AVPacket *out)
+{
+ VP9SFSplitContext *s = ctx->priv_data;
+ AVPacket *in;
+ int i, j, ret, marker;
+ int is_superframe = !!s->buffer_pkt;
+
+ if (!s->buffer_pkt) {
+ ret = ff_bsf_get_packet(ctx, &s->buffer_pkt);
+ if (ret < 0)
+ return ret;
+ in = s->buffer_pkt;
+
+ marker = in->data[in->size - 1];
+ if ((marker & 0xe0) == 0xc0) {
+ int length_size = 1 + ((marker >> 3) & 0x3);
+ int nb_frames = 1 + (marker & 0x7);
+ int idx_size = 2 + nb_frames * length_size;
+
+ if (in->size >= idx_size && in->data[in->size - idx_size] == marker) {
+ GetByteContext bc;
+ int total_size = 0;
+
+ bytestream2_init(&bc, in->data + in->size + 1 - idx_size,
+ nb_frames * length_size);
+
+ for (i = 0; i < nb_frames; i++) {
+ int frame_size = 0;
+ for (j = 0; j < length_size; j++)
+ frame_size |= bytestream2_get_byte(&bc) << (j * 8);
+
+ total_size += frame_size;
+ if (total_size > in->size - idx_size) {
+ av_log(ctx, AV_LOG_ERROR,
+ "Invalid frame size in a superframe: %d\n", frame_size);
+ ret = AVERROR(EINVAL);
+ goto fail;
+ }
+ s->sizes[i] = frame_size;
+ }
+ s->nb_frames = nb_frames;
+ s->next_frame = 0;
+ s->next_frame_offset = 0;
+ is_superframe = 1;
+ }
+ }
+ }
+
+ if (is_superframe) {
+ BitstreamContext bc;
+ int profile, invisible = 0;
+
+ ret = av_packet_ref(out, s->buffer_pkt);
+ if (ret < 0)
+ goto fail;
+
+ out->data += s->next_frame_offset;
+ out->size = s->sizes[s->next_frame];
+
+ s->next_frame_offset += out->size;
+ s->next_frame++;
+
+ if (s->next_frame >= s->nb_frames)
+ av_packet_free(&s->buffer_pkt);
+
+ ret = bitstream_init8(&bc, out->data, out->size);
+ if (ret < 0)
+ goto fail;
+
+ bitstream_read(&bc, 2); // frame_marker
+ profile = bitstream_read(&bc, 1);
+ profile |= bitstream_read(&bc, 1) << 1;
+ if (profile == 3)
+ bitstream_read(&bc, 1);
+ if (!bitstream_read(&bc, 1)) {
+ bitstream_read(&bc, 1);
+ invisible = !bitstream_read(&bc, 1);
+ }
+
+ if (invisible)
+ out->pts = AV_NOPTS_VALUE;
+
+ } else {
+ av_packet_move_ref(out, s->buffer_pkt);
+ av_packet_free(&s->buffer_pkt);
+ }
+
+ return 0;
+fail:
+ av_packet_free(&s->buffer_pkt);
+ return ret;
+}
+
+static void vp9_superframe_split_uninit(AVBSFContext *ctx)
+{
+ VP9SFSplitContext *s = ctx->priv_data;
+ av_packet_free(&s->buffer_pkt);
+}
+
+const AVBitStreamFilter ff_vp9_superframe_split_bsf = {
+ .name = "vp9_superframe_split",
+ .priv_data_size = sizeof(VP9SFSplitContext),
+ .close = vp9_superframe_split_uninit,
+ .filter = vp9_superframe_split_filter,
+ .codec_ids = (const enum AVCodecID []){ AV_CODEC_ID_VP9, AV_CODEC_ID_NONE },
+};
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