From 03a80925effc2698d21dc0b00290eecf42dd9e68 Mon Sep 17 00:00:00 2001 From: Anton Khirnov Date: Sun, 13 Nov 2016 11:00:02 +0100 Subject: lavc: add a bitstream filter for splitting VP9 superframes Partially based on code by Ronald S. Bultje . --- libavcodec/vp9_superframe_split_bsf.c | 146 ++++++++++++++++++++++++++++++++++ 1 file changed, 146 insertions(+) create mode 100644 libavcodec/vp9_superframe_split_bsf.c (limited to 'libavcodec/vp9_superframe_split_bsf.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 + +#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 }, +}; -- cgit v1.2.3