[FFmpeg-devel] [RFC][PATCH] libavformat: add librist protocol
Gijs Peskens
gijs at peskens.net
Mon Feb 22 10:10:20 EET 2021
Hi, some feedback from one of the libRIST developers:
Testing this patch (via diff found
on:https://patchwork.ffmpeg.org/project/ffmpeg/patch/20210126205145.20448-1-onemda@gmail.com/
) I've noticed FFmpeg is not reading fast enough from the libRIST FIFO
buffer (which is limited to 1024 packets) causing it to overrun.
Unfortunately libRIST had a bug where it kept incrementing the buffer
counter indefinitely, this has now been fixed and it will log an error
whenever this happens (which is very often with FFmpeg).
FFmpeg will need to read the FIFO faster, by calling the librist_read
function more often. If that's not possible within the design of FFmpeg
the module can either:
-use the callback (runs within a libRIST thread context) and store the
data_block ptrs in a FIFO
-dedicate a thread and store the data_block ptrs in a FIFO
The librist_read function can then pop from the fifo, copy out the data,
and free the block.
Also I suggest to set the default loglevel at least to RIST_LOG_ERROR
preferably at least to RIST_LOG_WARN.
I'd also suggest changing the default buffer size and the min/max
values, the unit is ms. I'd suggest a min of 1 (0 would select the
default of libRIST -> 1000) a max somewhere far out enough but limited
enough to prevent shooting in the foot (i.e.: 30 seconds worth) and a
default of 1000.
You can consider disabling advanced profile, libRIST limits profile to
MAIN atm, and advanced will likely not be out (VSF spec) before summer
(and quite likely much later).
How does FFmpeg handle multiplexed streams from libRIST currently? This
is not clear to me. I'd think at the very least FFmpeg would need to
allow the user to filter to 1 stream based on the tunneled destination
port number, as the RIST protocol allows multiple streams to be tunneled
into 1 MAIN profile session.
Personally I'd also like to be able to get the stats out of ffmpeg, an
option for that would be very welcome (simply writing out to a file
would be very helpful).
Sincerely,
Gijs Peskens
On 22-12-2020 19:09, onemda at gmail.com (Paul B Mahol) wrote:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
> TODO:
> What about logging messages?
> Return codes?
> File handles?
> Add support for password?
> Advanced stuff?
>
> ---
> configure | 5 ++
> libavformat/Makefile | 1 +
> libavformat/librist.c | 164 ++++++++++++++++++++++++++++++++++++++++
> libavformat/protocols.c | 1 +
> 4 files changed, 171 insertions(+)
> create mode 100644 libavformat/librist.c
>
> diff --git a/configure b/configure
> index 90914752f1..462f2dcf64 100755
> --- a/configure
> +++ b/configure
> @@ -259,6 +259,7 @@ External library support:
> --enable-libpulse enable Pulseaudio input via libpulse [no]
> --enable-librabbitmq enable RabbitMQ library [no]
> --enable-librav1e enable AV1 encoding via rav1e [no]
> + --enable-librist enable RIST via librist [no]
> --enable-librsvg enable SVG rasterization via librsvg [no]
> --enable-librubberband enable rubberband needed for rubberband filter [no]
> --enable-librtmp enable RTMP[E] support via librtmp [no]
> @@ -1797,6 +1798,7 @@ EXTERNAL_LIBRARY_LIST="
> libpulse
> librabbitmq
> librav1e
> + librist
> librsvg
> librtmp
> libshine
> @@ -3488,6 +3490,8 @@ unix_protocol_select="network"
> # external library protocols
> libamqp_protocol_deps="librabbitmq"
> libamqp_protocol_select="network"
> +librist_protocol_deps="librist"
> +librist_protocol_select="network"
> librtmp_protocol_deps="librtmp"
> librtmpe_protocol_deps="librtmp"
> librtmps_protocol_deps="librtmp"
> @@ -6404,6 +6408,7 @@ enabled libopus && {
> enabled libpulse && require_pkg_config libpulse libpulse pulse/pulseaudio.h pa_context_new
> enabled librabbitmq && require_pkg_config librabbitmq "librabbitmq >= 0.7.1" amqp.h amqp_new_connection
> enabled librav1e && require_pkg_config librav1e "rav1e >= 0.1.0" rav1e.h rav1e_context_new
> +enabled librist && require_pkg_config librist "librist >= 0.2" librist/librist.h rist_receiver_create
> enabled librsvg && require_pkg_config librsvg librsvg-2.0 librsvg-2.0/librsvg/rsvg.h rsvg_handle_render_cairo
> enabled librtmp && require_pkg_config librtmp librtmp librtmp/rtmp.h RTMP_Socket
> enabled librubberband && require_pkg_config librubberband "rubberband >= 1.8.1" rubberband/rubberband-c.h rubberband_new -lstdc++ && append librubberband_extralibs "-lstdc++"
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index 97d868081b..799e16c59e 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -652,6 +652,7 @@ OBJS-$(CONFIG_UNIX_PROTOCOL) += unix.o
>
> # external library protocols
> OBJS-$(CONFIG_LIBAMQP_PROTOCOL) += libamqp.o
> +OBJS-$(CONFIG_LIBRIST_PROTOCOL) += librist.o
> OBJS-$(CONFIG_LIBRTMP_PROTOCOL) += librtmp.o
> OBJS-$(CONFIG_LIBRTMPE_PROTOCOL) += librtmp.o
> OBJS-$(CONFIG_LIBRTMPS_PROTOCOL) += librtmp.o
> diff --git a/libavformat/librist.c b/libavformat/librist.c
> new file mode 100644
> index 0000000000..b07f1ab673
> --- /dev/null
> +++ b/libavformat/librist.c
> @@ -0,0 +1,164 @@
> +/*
> + * 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
> + */
> +
> +/**
> + * @file
> + * Reliable Internet Streaming Transport protocol
> + */
> +
> +#include "libavutil/avassert.h"
> +#include "libavutil/opt.h"
> +#include "libavutil/parseutils.h"
> +#include "libavutil/time.h"
> +
> +#include "avformat.h"
> +#include "internal.h"
> +#include "network.h"
> +#include "os_support.h"
> +#include "url.h"
> +
> +#include <librist/librist.h>
> +
> +typedef struct RISTContext {
> + const AVClass *class;
> + int fd;
> +
> + int profile;
> +
> + const struct rist_peer_config *peer_config;
> + struct rist_peer *peer;
> + struct rist_ctx *rist_ctx;
> +} RISTContext;
> +
> +#define D AV_OPT_FLAG_DECODING_PARAM
> +#define E AV_OPT_FLAG_ENCODING_PARAM
> +#define OFFSET(x) offsetof(RISTContext, x)
> +static const AVOption librist_options[] = {
> + { "profile", "set RIST profile", OFFSET(profile), AV_OPT_TYPE_INT, {.i64=RIST_PROFILE_SIMPLE}, 0, 2, .flags = D|E },
> + { NULL }
> +};
> +
> +static int librist_open(URLContext *h, const char *uri, int flags)
> +{
> + RISTContext *s = h->priv_data;
> + int ret;
> +
> + if (flags & AVIO_FLAG_WRITE) {
> + ret = rist_sender_create(&s->rist_ctx, s->profile, 0, NULL);
> + if (ret < 0)
> + return ret;
> + } else {
> + ret = rist_receiver_create(&s->rist_ctx, s->profile, NULL);
> + if (ret < 0)
> + return ret;
> + }
> +
> + ret = rist_parse_address(uri, &s->peer_config);
> + if (ret < 0)
> + return ret;
> +
> + ret = rist_peer_create(s->rist_ctx, &s->peer, s->peer_config);
> + if (ret < 0)
> + return ret;
> +
> + ret = rist_start(s->rist_ctx);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int librist_read(URLContext *h, uint8_t *buf, int size)
> +{
> + RISTContext *s = h->priv_data;
> + const struct rist_data_block *data_block;
> + int ret;
> +
> + ret = rist_receiver_data_read(s->rist_ctx, &data_block, 5);
> + if (ret < 0)
> + return ret;
> +
> + if (ret > 0) {
> + memcpy(buf, data_block->payload, data_block->payload_len);
> + return data_block->payload_len;
> + }
> +
> + return 0;
> +}
> +
> +static int librist_write(URLContext *h, const uint8_t *buf, int size)
> +{
> + RISTContext *s = h->priv_data;
> + struct rist_data_block data_block = { 0 };
> + int ret;
> +
> + data_block.ts_ntp = 0;
> + data_block.payload = buf;
> + data_block.payload_len = size;
> + ret = rist_sender_data_write(s->rist_ctx, &data_block);
> + if (ret < 0)
> + return ret;
> + return size; // XXX should be ret actually but librist is buggy, got OOM otherwise
> +}
> +
> +static int librist_close(URLContext *h)
> +{
> + RISTContext *s = h->priv_data;
> + int ret;
> +
> + free((void *)s->peer_config);
> + s->peer_config = NULL;
> +
> + ret = rist_peer_destroy(s->rist_ctx, s->peer);
> + if (ret < 0)
> + return ret;
> + s->peer = NULL;
> +
> + ret = rist_destroy(s->rist_ctx);
> + if (ret < 0)
> + return ret;
> + s->rist_ctx = NULL;
> +
> + return 0;
> +}
> +
> +static int librist_get_file_handle(URLContext *h)
> +{
> + RISTContext *s = h->priv_data;
> +
> + return s->fd;
> +}
> +
> +static const AVClass librist_class = {
> + .class_name = "librist",
> + .item_name = av_default_item_name,
> + .option = librist_options,
> + .version = LIBAVUTIL_VERSION_INT,
> +};
> +
> +const URLProtocol ff_librist_protocol = {
> + .name = "rist",
> + .url_open = librist_open,
> + .url_read = librist_read,
> + .url_write = librist_write,
> + .url_close = librist_close,
> + .url_get_file_handle = librist_get_file_handle,
> + .priv_data_size = sizeof(RISTContext),
> + .flags = URL_PROTOCOL_FLAG_NETWORK,
> + .priv_data_class = &librist_class,
> +};
> diff --git a/libavformat/protocols.c b/libavformat/protocols.c
> index 7df18fbb3b..c4fc446bb6 100644
> --- a/libavformat/protocols.c
> +++ b/libavformat/protocols.c
> @@ -61,6 +61,7 @@ extern const URLProtocol ff_udp_protocol;
> extern const URLProtocol ff_udplite_protocol;
> extern const URLProtocol ff_unix_protocol;
> extern const URLProtocol ff_libamqp_protocol;
> +extern const URLProtocol ff_librist_protocol;
> extern const URLProtocol ff_librtmp_protocol;
> extern const URLProtocol ff_librtmpe_protocol;
> extern const URLProtocol ff_librtmps_protocol;
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