Lightningbeam/lightningbeam-ui/gpu-video-encoder/src/encoder.rs

293 lines
12 KiB
Rust

//! End-to-end zero-copy H.264 encoder: render an RGBA wgpu texture straight into a VAAPI
//! NV12 surface (no CPU copy) and encode it with `h264_vaapi`. The caller renders frames
//! on [`ZeroCopyEncoder::device`] (the custom Vulkan device with DMA-BUF import enabled).
//!
//! Imports are cached by VASurface id, so the pooled surfaces are imported once each.
use crate::dmabuf::{self, ImportedNv12, Nv12DmaBuf};
use crate::render_nv12::Rgba2Nv12;
use crate::vk_device::{self, DrmDevice};
use ffmpeg_sys_next as ff;
use std::collections::HashMap;
use std::ffi::CString;
use std::path::Path;
use std::ptr;
#[inline]
fn averror(e: i32) -> i32 {
-e
}
pub struct ZeroCopyEncoder {
drm: DrmDevice,
renderer: Rgba2Nv12,
hw_device: *mut ff::AVBufferRef,
frames_ref: *mut ff::AVBufferRef,
enc: *mut ff::AVCodecContext,
pkt: *mut ff::AVPacket,
/// Output container (e.g. `.mp4`); packets are muxed into it directly.
oc: *mut ff::AVFormatContext,
enc_tb: ff::AVRational,
stream_tb: ff::AVRational,
width: u32,
height: u32,
pts: i64,
cache: HashMap<usize, ImportedNv12>,
}
// The encoder owns its FFmpeg contexts (raw `*mut`) and Vulkan/wgpu handles exclusively; it is
// never shared, only moved. Sending it to a dedicated export thread is sound.
unsafe impl Send for ZeroCopyEncoder {}
impl ZeroCopyEncoder {
/// Build a zero-copy `h264_vaapi` encoder writing to `output_path` (container inferred
/// from the extension, e.g. `.mp4`). `Err` if VAAPI/the device is unavailable.
pub fn new(
width: u32,
height: u32,
framerate: i32,
bitrate_kbps: u32,
output_path: &Path,
) -> Result<Self, String> {
let drm = vk_device::create()?;
let renderer = Rgba2Nv12::new(&drm.device);
unsafe {
let mut hw_device = crate::vaapi::create_device()?;
let name = CString::new("h264_vaapi").unwrap();
let codec = ff::avcodec_find_encoder_by_name(name.as_ptr());
if codec.is_null() {
ff::av_buffer_unref(&mut hw_device);
return Err("h264_vaapi not found".into());
}
let enc = ff::avcodec_alloc_context3(codec);
(*enc).width = width as i32;
(*enc).height = height as i32;
(*enc).time_base = ff::AVRational { num: 1, den: framerate };
(*enc).framerate = ff::AVRational { num: framerate, den: 1 };
(*enc).pix_fmt = ff::AVPixelFormat::AV_PIX_FMT_VAAPI;
(*enc).bit_rate = (bitrate_kbps as i64) * 1000;
let frames_ref = ff::av_hwframe_ctx_alloc(hw_device);
{
let fctx = (*frames_ref).data as *mut ff::AVHWFramesContext;
(*fctx).format = ff::AVPixelFormat::AV_PIX_FMT_VAAPI;
(*fctx).sw_format = ff::AVPixelFormat::AV_PIX_FMT_NV12;
(*fctx).width = width as i32;
(*fctx).height = height as i32;
(*fctx).initial_pool_size = 16;
}
if ff::av_hwframe_ctx_init(frames_ref) < 0 {
let mut fr = frames_ref;
ff::av_buffer_unref(&mut fr);
ff::avcodec_free_context(&mut (enc as *mut _));
ff::av_buffer_unref(&mut hw_device);
return Err("av_hwframe_ctx_init failed".into());
}
(*enc).hw_frames_ctx = ff::av_buffer_ref(frames_ref);
// Output container (format inferred from the path's extension).
let cleanup = |frames_ref: *mut ff::AVBufferRef, enc: *mut ff::AVCodecContext, hw: *mut ff::AVBufferRef| {
let mut fr = frames_ref;
ff::av_buffer_unref(&mut fr);
ff::avcodec_free_context(&mut (enc as *mut _));
let mut h = hw;
ff::av_buffer_unref(&mut h);
};
let path_c = CString::new(output_path.to_string_lossy().as_ref()).unwrap();
let mut oc: *mut ff::AVFormatContext = ptr::null_mut();
if ff::avformat_alloc_output_context2(&mut oc, ptr::null(), ptr::null(), path_c.as_ptr()) < 0
|| oc.is_null()
{
cleanup(frames_ref, enc, hw_device);
return Err(format!("avformat_alloc_output_context2 for {output_path:?} failed"));
}
// mp4/mov want SPS/PPS in extradata, not inline — set before opening the encoder.
if (*(*oc).oformat).flags & ff::AVFMT_GLOBALHEADER as i32 != 0 {
(*enc).flags |= ff::AV_CODEC_FLAG_GLOBAL_HEADER as i32;
}
if ff::avcodec_open2(enc, codec, ptr::null_mut()) < 0 {
ff::avformat_free_context(oc);
cleanup(frames_ref, enc, hw_device);
return Err("avcodec_open2(h264_vaapi) failed".into());
}
let stream = ff::avformat_new_stream(oc, codec);
if stream.is_null() {
ff::avformat_free_context(oc);
cleanup(frames_ref, enc, hw_device);
return Err("avformat_new_stream failed".into());
}
if ff::avcodec_parameters_from_context((*stream).codecpar, enc) < 0 {
ff::avformat_free_context(oc);
cleanup(frames_ref, enc, hw_device);
return Err("avcodec_parameters_from_context failed".into());
}
(*stream).time_base = (*enc).time_base;
if ff::avio_open(&mut (*oc).pb, path_c.as_ptr(), ff::AVIO_FLAG_WRITE as i32) < 0 {
ff::avformat_free_context(oc);
cleanup(frames_ref, enc, hw_device);
return Err(format!("avio_open {output_path:?} failed"));
}
if ff::avformat_write_header(oc, ptr::null_mut()) < 0 {
ff::avio_closep(&mut (*oc).pb);
ff::avformat_free_context(oc);
cleanup(frames_ref, enc, hw_device);
return Err("avformat_write_header failed".into());
}
// The muxer may rewrite the stream time_base in write_header.
let stream_tb = (*stream).time_base;
Ok(Self {
drm,
renderer,
hw_device,
frames_ref,
enc,
pkt: ff::av_packet_alloc(),
oc,
enc_tb: (*enc).time_base,
stream_tb,
width,
height,
pts: 0,
cache: HashMap::new(),
})
}
}
/// The wgpu device frames must be rendered on (so the RGBA texture is importable).
pub fn device(&self) -> &wgpu::Device {
&self.drm.device
}
pub fn queue(&self) -> &wgpu::Queue {
&self.drm.queue
}
/// Render `rgba` (an `Rgba8Unorm` texture on [`Self::device`], `TEXTURE_BINDING`)
/// into a VAAPI surface and encode it. Appends any produced packets internally.
pub fn encode_rgba(&mut self, rgba: &wgpu::Texture) -> Result<(), String> {
unsafe {
let surf = ff::av_frame_alloc();
if ff::av_hwframe_get_buffer(self.frames_ref, surf, 0) < 0 {
ff::av_frame_free(&mut (surf as *mut _));
return Err("av_hwframe_get_buffer failed".into());
}
let id = (*surf).data[3] as usize; // VASurfaceID
if !self.cache.contains_key(&id) {
let drm_f = ff::av_frame_alloc();
(*drm_f).format = ff::AVPixelFormat::AV_PIX_FMT_DRM_PRIME as i32;
let flags = ff::AV_HWFRAME_MAP_DIRECT as i32
| ff::AV_HWFRAME_MAP_READ as i32
| ff::AV_HWFRAME_MAP_WRITE as i32;
if ff::av_hwframe_map(drm_f, surf, flags) < 0 {
ff::av_frame_free(&mut (drm_f as *mut _));
ff::av_frame_free(&mut (surf as *mut _));
return Err("av_hwframe_map failed".into());
}
let desc = (*drm_f).data[0] as *const ff::AVDRMFrameDescriptor;
let obj = &(*desc).objects[0];
let y = &(*desc).layers[0].planes[0];
let uv = &(*desc).layers[1].planes[0];
let buf = Nv12DmaBuf {
fd: obj.fd,
size: obj.size as u64,
modifier: obj.format_modifier,
width: self.width,
height: self.height,
y_offset: y.offset as u64,
y_pitch: y.pitch as u64,
uv_offset: uv.offset as u64,
uv_pitch: uv.pitch as u64,
};
let imported = match dmabuf::import_raw(&self.drm, &buf) {
Ok(i) => i,
Err(e) => {
ff::av_frame_free(&mut (drm_f as *mut _));
ff::av_frame_free(&mut (surf as *mut _));
return Err(e);
}
};
ff::av_frame_free(&mut (drm_f as *mut _)); // fd was dup'd into Vulkan
self.cache.insert(id, imported);
}
// Render RGBA -> NV12 directly into the surface planes.
let imp = self.cache.get(&id).unwrap();
let rgba_view = rgba.create_view(&Default::default());
let y_view = imp.y().create_view(&Default::default());
let uv_view = imp.uv().create_view(&Default::default());
let mut cmd = self.drm.device.create_command_encoder(&Default::default());
self.renderer.convert(&self.drm.device, &mut cmd, &rgba_view, &y_view, &uv_view);
self.drm.queue.submit(Some(cmd.finish()));
let _ = self.drm.device.poll(wgpu::PollType::wait_indefinitely());
// Encode the surface.
(*surf).pts = self.pts;
self.pts += 1;
let r = ff::avcodec_send_frame(self.enc, surf);
ff::av_frame_free(&mut (surf as *mut _));
if r < 0 {
return Err(format!("avcodec_send_frame failed: {r}"));
}
self.drain()
}
}
unsafe fn drain(&mut self) -> Result<(), String> {
loop {
let r = ff::avcodec_receive_packet(self.enc, self.pkt);
if r == averror(libc::EAGAIN) || r == ff::AVERROR_EOF {
break;
}
if r < 0 {
return Err(format!("avcodec_receive_packet failed: {r}"));
}
ff::av_packet_rescale_ts(self.pkt, self.enc_tb, self.stream_tb);
(*self.pkt).stream_index = 0;
// Takes ownership of the packet's buffer (unrefs it for us).
let w = ff::av_interleaved_write_frame(self.oc, self.pkt);
if w < 0 {
return Err(format!("av_interleaved_write_frame failed: {w}"));
}
}
Ok(())
}
/// Flush the encoder, write the container trailer, and close the output file.
pub fn finish(mut self) -> Result<(), String> {
unsafe {
ff::avcodec_send_frame(self.enc, ptr::null_mut());
self.drain()?;
if ff::av_write_trailer(self.oc) < 0 {
return Err("av_write_trailer failed".into());
}
ff::avio_closep(&mut (*self.oc).pb);
}
Ok(())
}
}
impl Drop for ZeroCopyEncoder {
fn drop(&mut self) {
unsafe {
self.cache.clear(); // frees imported Vulkan resources first
ff::av_packet_free(&mut (self.pkt as *mut _));
ff::avcodec_free_context(&mut (self.enc as *mut _));
let mut fr = self.frames_ref;
ff::av_buffer_unref(&mut fr);
ff::av_buffer_unref(&mut self.hw_device);
if !self.oc.is_null() {
// `finish` nulls pb via avio_closep; close here too if it wasn't called.
if !(*self.oc).pb.is_null() {
ff::avio_closep(&mut (*self.oc).pb);
}
ff::avformat_free_context(self.oc);
self.oc = ptr::null_mut();
}
}
}
}