gst-plugins-rs/generic/fmp4/examples/dash_vod.rs

267 lines
11 KiB
Rust
Raw Normal View History

// Copyright (C) 2021 Sebastian Dröge <sebastian@centricular.com>
//
// This Source Code Form is subject to the terms of the Mozilla Public License, v2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at
// <https://mozilla.org/MPL/2.0/>.
//
// SPDX-License-Identifier: MPL-2.0
// This creates a VoD DASH manifest based on the output of `cmafmux`. The media header
// ("initialization segment") is written into a separate file as the segments, and each segment is
// its own file too.
//
// All segments that are created are exactly 10s, expect for the last one which is only 3.333s.
use gst::prelude::*;
use std::fmt::Write;
use std::path::PathBuf;
use std::sync::{Arc, Mutex};
use anyhow::Error;
struct Segment {
start_time: gst::ClockTime,
duration: gst::ClockTime,
}
struct State {
start_time: Option<gst::ClockTime>,
end_time: Option<gst::ClockTime>,
segments: Vec<Segment>,
path: PathBuf,
}
fn main() -> Result<(), Error> {
gst::init()?;
gstfmp4::plugin_register_static()?;
let state = Arc::new(Mutex::new(State {
start_time: None,
end_time: None,
segments: Vec::new(),
path: PathBuf::from("dash_stream"),
}));
let pipeline = gst::parse_launch("videotestsrc num-buffers=2500 ! timecodestamper ! video/x-raw,format=I420,width=1280,height=720,framerate=30/1 ! timeoverlay ! x264enc bframes=0 bitrate=2048 ! video/x-h264,profile=main ! cmafmux fragment-duration=10000000000 header-update-mode=update write-mehd=true ! appsink name=sink").unwrap().downcast::<gst::Pipeline>().unwrap();
let sink = pipeline
.by_name("sink")
.unwrap()
.dynamic_cast::<gst_app::AppSink>()
.unwrap();
sink.set_buffer_list(true);
let state_clone = state.clone();
sink.set_callbacks(
gst_app::AppSinkCallbacks::builder()
.new_sample(move |sink| {
let sample = sink.pull_sample().map_err(|_| gst::FlowError::Eos)?;
let mut state = state.lock().unwrap();
// The muxer only outputs non-empty buffer lists
let mut buffer_list = sample.buffer_list_owned().expect("no buffer list");
assert!(!buffer_list.is_empty());
let mut first = buffer_list.get(0).unwrap();
// Each list contains a full segment, i.e. does not start with a DELTA_UNIT
assert!(!first.flags().contains(gst::BufferFlags::DELTA_UNIT));
// If the buffer has the DISCONT and HEADER flag set then it contains the media
// header, i.e. the `ftyp`, `moov` and other media boxes.
//
// This might be the initial header or the updated header at the end of the stream.
if first.flags().contains(gst::BufferFlags::DISCONT | gst::BufferFlags::HEADER) {
let mut path = state.path.clone();
std::fs::create_dir_all(&path).expect("failed to create directory");
path.push("init.cmfi");
println!("writing header to {}", path.display());
let map = first.map_readable().unwrap();
std::fs::write(path, &map).expect("failed to write header");
drop(map);
// Remove the header from the buffer list
buffer_list.make_mut().remove(0, 1);
// If the list is now empty then it only contained the media header and nothing
// else.
if buffer_list.is_empty() {
return Ok(gst::FlowSuccess::Ok);
}
// Otherwise get the next buffer and continue working with that.
first = buffer_list.get(0).unwrap();
}
// If the buffer only has the HEADER flag set then this is a segment header that is
// followed by one or more actual media buffers.
assert!(first.flags().contains(gst::BufferFlags::HEADER));
let segment = sample.segment().expect("no segment")
.downcast_ref::<gst::ClockTime>().expect("no time segment");
// Initialize the start time with the first PTS we observed. This will be used
// later for calculating the duration of the whole media for the DASH manifest.
//
// The PTS of the segment header is equivalent to the earliest PTS of the whole
// segment.
let pts = segment.to_running_time(first.pts().unwrap()).expect("can't get running time");
if state.start_time.is_none() {
state.start_time = Some(pts);
}
// The metadata of the first media buffer is duplicated to the segment header.
// Based on this we can know the timecode of the first frame in this segment.
let meta = first.meta::<gst_video::VideoTimeCodeMeta>().expect("no timecode meta");
let mut path = state.path.clone();
path.push(format!("segment_{}.cmfv", state.segments.len() + 1));
println!("writing segment with timecode {} to {}", meta.tc(), path.display());
// Calculate the end time at this point. The duration of the segment header is set
// to the whole duration of this segment.
let duration = first.duration().unwrap();
let end_time = first.pts().unwrap() + first.duration().unwrap();
state.end_time = Some(segment.to_running_time(end_time).expect("can't get running time"));
let mut file = std::fs::File::create(path).expect("failed to open fragment");
for buffer in &*buffer_list {
use std::io::prelude::*;
let map = buffer.map_readable().unwrap();
file.write_all(&map).expect("failed to write fragment");
}
state.segments.push(Segment {
start_time: pts,
duration,
});
Ok(gst::FlowSuccess::Ok)
})
.eos(move |_sink| {
let state = state_clone.lock().unwrap();
// Now write the manifest
let mut path = state.path.clone();
path.push("manifest.mpd");
println!("writing manifest to {}", path.display());
let duration = state.end_time.opt_checked_sub(state.start_time).ok().flatten().unwrap().mseconds() as f64 / 1000.0;
// Write the whole segment timeline out here, compressing multiple segments with
// the same duration to a repeated segment.
let mut segment_timeline = String::new();
let mut write_segment = |start: gst::ClockTime, duration: gst::ClockTime, repeat: usize| {
if repeat > 0 {
writeln!(
&mut segment_timeline,
" <S t=\"{time}\" d=\"{duration}\" r=\"{repeat}\" />",
time = start.mseconds(),
duration = duration.mseconds(),
repeat = repeat
).unwrap();
} else {
writeln!(
&mut segment_timeline,
" <S t=\"{time}\" d=\"{duration}\" />",
time = start.mseconds(),
duration = duration.mseconds()
).unwrap();
}
};
let mut start = None;
let mut num_segments = 0;
let mut last_duration = None;
for segment in &state.segments {
if start.is_none() {
start = Some(segment.start_time);
}
if last_duration.is_none() {
last_duration = Some(segment.duration);
}
// If the duration of this segment is different from the previous one then we
// have to write out the segment now.
if last_duration != Some(segment.duration) {
write_segment(start.unwrap(), last_duration.unwrap(), num_segments - 1);
start = Some(segment.start_time);
last_duration = Some(segment.duration);
num_segments = 1;
} else {
num_segments += 1;
}
}
// Write the last segment if any
if num_segments > 0 {
write_segment(start.unwrap(), last_duration.unwrap(), num_segments - 1);
}
let manifest = format!(r###"<?xml version="1.0" encoding="UTF-8"?>
<MPD
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="urn:mpeg:dash:schema:mpd:2011"
xsi:schemaLocation="urn:mpeg:dash:schema:mpd:2011 DASH-MPD.xsd"
type="static"
mediaPresentationDuration="PT{duration:.3}S"
profiles="urn:mpeg:dash:profile:isoff-on-demand:2011">
<Period>
<AdaptationSet mimeType="video/mp4" codecs="avc1.4d0228" frameRate="30/1" segmentAlignment="true" startWithSAP="1">
<Representation id="A" bandwidth="2048000" with="1280" height="720">
<SegmentTemplate timescale="1000" initialization="init.cmfi" media="segment_$Number$.cmfv">
<SegmentTimeline>
{segment_timeline} </SegmentTimeline>
</SegmentTemplate>
</Representation>
</AdaptationSet>
</Period>
</MPD>
"###,
duration = duration, segment_timeline = segment_timeline);
std::fs::write(path, &manifest).expect("failed to write manifest");
})
.build(),
);
pipeline.set_state(gst::State::Playing)?;
let bus = pipeline
.bus()
.expect("Pipeline without bus. Shouldn't happen!");
for msg in bus.iter_timed(gst::ClockTime::NONE) {
use gst::MessageView;
match msg.view() {
MessageView::Eos(..) => {
println!("EOS");
break;
}
MessageView::Error(err) => {
pipeline.set_state(gst::State::Null)?;
eprintln!(
"Got error from {}: {} ({})",
msg.src()
.map(|s| String::from(s.path_string()))
.unwrap_or_else(|| "None".into()),
2021-12-02 20:31:52 +00:00
err.error(),
err.debug().unwrap_or_else(|| "".into()),
);
break;
}
_ => (),
}
}
pipeline.set_state(gst::State::Null)?;
Ok(())
}