[FFmpeg-devel] [PATCH 5/5] avformat: add an AV1 Annex B demuxer
Andreas Rheinhardt
andreas.rheinhardt at gmail.com
Mon Nov 11 21:28:00 EET 2019
James Almer:
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> configure | 1 +
> libavformat/Makefile | 1 +
> libavformat/allformats.c | 1 +
> libavformat/obu.c | 276 +++++++++++++++++++++++++++++++++++++++
> 4 files changed, 279 insertions(+)
> create mode 100644 libavformat/obu.c
>
> diff --git a/configure b/configure
> index 70f60997c1..a8dbba879d 100755
> --- a/configure
> +++ b/configure
> @@ -3293,6 +3293,7 @@ mxf_d10_muxer_select="mxf_muxer"
> mxf_opatom_muxer_select="mxf_muxer"
> nut_muxer_select="riffenc"
> nuv_demuxer_select="riffdec"
> +obu_demuxer_select="av1_frame_merge_bsf"
> oga_muxer_select="ogg_muxer"
> ogg_demuxer_select="dirac_parse"
> ogv_muxer_select="ogg_muxer"
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index 8251f8f657..9057d0358a 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -350,6 +350,7 @@ OBJS-$(CONFIG_NULL_MUXER) += nullenc.o
> OBJS-$(CONFIG_NUT_DEMUXER) += nutdec.o nut.o isom.o
> OBJS-$(CONFIG_NUT_MUXER) += nutenc.o nut.o
> OBJS-$(CONFIG_NUV_DEMUXER) += nuv.o
> +OBJS-$(CONFIG_OBU_DEMUXER) += obu.o
> OBJS-$(CONFIG_OGG_DEMUXER) += oggdec.o \
> oggparsecelt.o \
> oggparsedaala.o \
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index f7fea32b45..152644e9f9 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -282,6 +282,7 @@ extern AVInputFormat ff_nut_demuxer;
> extern AVOutputFormat ff_nut_muxer;
> extern AVInputFormat ff_nuv_demuxer;
> extern AVOutputFormat ff_oga_muxer;
> +extern AVInputFormat ff_obu_demuxer;
> extern AVInputFormat ff_ogg_demuxer;
> extern AVOutputFormat ff_ogg_muxer;
> extern AVOutputFormat ff_ogv_muxer;
> diff --git a/libavformat/obu.c b/libavformat/obu.c
> new file mode 100644
> index 0000000000..55a9c7d55f
> --- /dev/null
> +++ b/libavformat/obu.c
> @@ -0,0 +1,276 @@
> +/*
> + * AV1 Annex-B demuxer
> + * Copyright (c) 2019 James Almer <jamrial at gmail.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 "config.h"
> +
> +#include "libavutil/common.h"
> +#include "libavutil/opt.h"
> +#include "libavcodec/av1_parse.h"
> +#include "avformat.h"
> +#include "avio_internal.h"
> +#include "internal.h"
> +
> +typedef struct AnnexBContext {
> + const AVClass *class;
> + AVBSFContext *bsf;
> + uint32_t temporal_unit_size;
> + uint32_t frame_unit_size;
> + AVRational framerate;
> +} AnnexBContext;
> +
> +static int leb(AVIOContext *pb, uint32_t *len) {
> + int more, i = 0;
> + uint8_t byte;
> + *len = 0;
> + do {
> + unsigned bits;
> + byte = avio_r8(pb);
> + more = byte & 0x80;
> + bits = byte & 0x7f;
> + if (i <= 3 || (i == 4 && bits < (1 << 4)))
> + *len |= bits << (i * 7);
> + else if (bits)
> + return AVERROR_INVALIDDATA;
> + if (++i == 8 && more)
> + return AVERROR_INVALIDDATA;
> + if (pb->eof_reached || pb->error)
> + return pb->error ? pb->error : AVERROR(EIO);
> + } while (more);
> + return i;
> +}
> +
> +static int read_obu(const uint8_t *buf, int size, int64_t *obu_size, int *type)
> +{
> + int start_pos, temporal_id, spatial_id;
> + int len;
> +
> + len = parse_obu_header(buf, size, obu_size, &start_pos,
> + type, &temporal_id, &spatial_id);
> + if (len < 0)
> + return len;
> +
> + return 0;
> +}
> +
> +static int annexb_probe(const AVProbeData *p)
> +{
> + AVIOContext pb;
> + int64_t obu_size;
> + uint32_t temporal_unit_size, frame_unit_size, obu_unit_size;
> + int seq = 0, frame_header = 0;
> + int ret, type, cnt = 0;
> +
> + ffio_init_context(&pb, p->buf, p->buf_size, 0,
> + NULL, NULL, NULL, NULL);
> +
> + ret = leb(&pb, &temporal_unit_size);
> + if (ret < 0)
> + return 0;
> + cnt += ret;
> + ret = leb(&pb, &frame_unit_size);
> + if (ret < 0 || (frame_unit_size + ret) > temporal_unit_size)
> + return 0;
> + cnt += ret;
> + temporal_unit_size -= ret;
> + ret = leb(&pb, &obu_unit_size);
> + if (ret < 0 || (obu_unit_size + ret) >= frame_unit_size)
> + return 0;
> + cnt += ret;
> +
> + temporal_unit_size -= obu_unit_size + ret;
> + frame_unit_size -= obu_unit_size + ret;
> +
> + avio_skip(&pb, obu_unit_size);
> + if (pb.eof_reached || pb.error)
> + return 0;
> +
> + // Check that the first OBU is a Temporal Delimiter.
> + ret = read_obu(p->buf + cnt, FFMIN(p->buf_size - cnt, obu_unit_size), &obu_size, &type);
> + if (ret < 0 || type != AV1_OBU_TEMPORAL_DELIMITER || obu_size > 0)
> + return 0;
> + cnt += obu_unit_size;
> +
> + do {
> + ret = leb(&pb, &obu_unit_size);
> + if (ret < 0 || (obu_unit_size + ret) > frame_unit_size)
> + return 0;
> + cnt += ret;
> +
> + avio_skip(&pb, obu_unit_size);
> + if (pb.eof_reached || pb.error)
> + return 0;
> +
> + ret = read_obu(p->buf + cnt, FFMIN(p->buf_size - cnt, obu_unit_size), &obu_size, &type);
> + if (ret < 0)
> + return 0;
> + cnt += obu_unit_size;
> +
> + if (type == AV1_OBU_SEQUENCE_HEADER)
> + seq = 1;
> + if (type == AV1_OBU_FRAME || type == AV1_OBU_FRAME_HEADER) {
> + if (frame_header || !seq)
> + return 0;
> + frame_header = 1;
> + break;
> + }
> + if (type == AV1_OBU_TILE_GROUP && !frame_header)
> + return 0;
> +
> + temporal_unit_size -= obu_unit_size + ret;
> + frame_unit_size -= obu_unit_size + ret;
> + } while (!seq || !frame_header || frame_unit_size);
> +
> + return (seq && frame_header) ? AVPROBE_SCORE_EXTENSION + 1 : 0;
> +}
> +
> +static int annexb_read_header(AVFormatContext *s)
> +{
> + AnnexBContext *c = s->priv_data;
> + const AVBitStreamFilter *filter = av_bsf_get_by_name("av1_frame_merge");
> + AVStream *st;
> + int ret;
> +
> + if (!filter) {
> + av_log(c, AV_LOG_ERROR, "av1_frame_merge bitstream filter "
> + "not found. This is a bug, please report it.\n");
> + return AVERROR_BUG;
> + }
> +
> + st = avformat_new_stream(s, NULL);
> + if (!st)
> + return AVERROR(ENOMEM);
> +
> + st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
> + st->codecpar->codec_id = AV_CODEC_ID_AV1;
> + st->need_parsing = AVSTREAM_PARSE_HEADERS;
> +
> + st->internal->avctx->framerate = c->framerate;
> + // taken from rawvideo demuxers
> + avpriv_set_pts_info(st, 64, 1, 1200000);
> +
> + ret = av_bsf_alloc(filter, &c->bsf);
> + if (ret < 0)
> + return ret;
> +
> + ret = avcodec_parameters_copy(c->bsf->par_in, st->codecpar);
> + if (ret < 0) {
> + av_bsf_free(&c->bsf);
> + return ret;
> + }
> +
> + return av_bsf_init(c->bsf);
Demuxers don't have a deinit function, so if av_bsf_init() fails, no
one will clean up after you and free the bsf.
> +}
> +
> +static int annexb_read_packet(AVFormatContext *s, AVPacket *pkt)
> +{
> + AnnexBContext *c = s->priv_data;
> + uint32_t obu_unit_size;
> + int ret, len;
> +
> +retry:
> + if (avio_feof(s->pb)) {
> + if (c->temporal_unit_size || c->frame_unit_size)
> + return AVERROR(EIO);
> + av_bsf_send_packet(c->bsf, NULL);
> + goto end;
> + }
> +
> + if (!c->temporal_unit_size) {
> + len = leb(s->pb, &c->temporal_unit_size);
> + if (len < 0) return AVERROR_INVALIDDATA;
> + }
> +
> + if (!c->frame_unit_size) {
> + len = leb(s->pb, &c->frame_unit_size);
> + if (len < 0 || (c->frame_unit_size + len) > c->temporal_unit_size)
> + return AVERROR_INVALIDDATA;
> + c->temporal_unit_size -= len;
> + }
> +
> + len = leb(s->pb, &obu_unit_size);
> + if (len < 0 || (obu_unit_size + len) > c->frame_unit_size)
> + return AVERROR_INVALIDDATA;
> +
> + ret = av_get_packet(s->pb, pkt, obu_unit_size);
> + if (ret < 0)
> + return ret;
> + if (ret != obu_unit_size) {
> + av_packet_unref(pkt);
This is unnecessary: ff_read_packet() will unref the packet if you
return an error. You added this yourself. (You are btw relying on this
by not unreferencing the packet if av_bsf_send_packet() fails.)
> + return AVERROR(EIO);
> + }
> +
> + c->temporal_unit_size -= obu_unit_size + len;
> + c->frame_unit_size -= obu_unit_size + len;
> +
> + ret = av_bsf_send_packet(c->bsf, pkt);
> + if (ret < 0) {
> + av_log(s, AV_LOG_ERROR, "av1_frame_merge filter "
> + "failed to send input packet\n");
"Failed to send packet to av1_frame_merge filter\n" (av1_frame_merge
does not send any input packet ever, it receives them; and this call
does not call any av1_frame_merge internal functions.)
> + return ret;
> + }
> +
> +end:
> + ret = av_bsf_receive_packet(c->bsf, pkt);
> +
> + if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF)
> + av_log(s, AV_LOG_ERROR, "av1_frame_merge filter "
> + "failed to receive output packet\n");
"av1_frame_merge filter failed to send output packet\n"
> +
> + if (ret == AVERROR(EAGAIN))
> + goto retry;
> +
> + return ret;
> +}
> +
> +static int annexb_read_close(AVFormatContext *s)
Side-note: Why does read_close() have to return an int? The return
value is ignored in avformat_close_input(), the only place where
read_close() is ever called.
I haven't looked at the rest (i.e. probe and leb) yet, in particular
wrt overflows.
- Andreas
More information about the ffmpeg-devel
mailing list