scrcpy/app/src/stream.c

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#include "stream.h"
#include <libavformat/avformat.h>
#include <libavutil/time.h>
#include <SDL2/SDL_assert.h>
#include <SDL2/SDL_events.h>
#include <SDL2/SDL_mutex.h>
#include <SDL2/SDL_thread.h>
#include <unistd.h>
#include "compat.h"
#include "config.h"
#include "buffer_util.h"
#include "decoder.h"
#include "events.h"
#include "lock_util.h"
#include "log.h"
#include "recorder.h"
#define BUFSIZE 0x10000
#define HEADER_SIZE 12
#define NO_PTS UINT64_C(-1)
static struct frame_meta *frame_meta_new(Uint64 pts) {
struct frame_meta *meta = malloc(sizeof(*meta));
if (!meta) {
return meta;
}
meta->pts = pts;
meta->next = NULL;
return meta;
}
static void frame_meta_delete(struct frame_meta *frame_meta) {
free(frame_meta);
}
static SDL_bool receiver_state_push_meta(struct receiver_state *state,
uint64_t pts) {
struct frame_meta *frame_meta = frame_meta_new(pts);
if (!frame_meta) {
return SDL_FALSE;
}
// append to the list
// (iterate to find the last item, in practice the list should be tiny)
struct frame_meta **p = &state->frame_meta_queue;
while (*p) {
p = &(*p)->next;
}
*p = frame_meta;
return SDL_TRUE;
}
static uint64_t receiver_state_take_meta(struct receiver_state *state) {
struct frame_meta *frame_meta = state->frame_meta_queue; // first item
SDL_assert(frame_meta); // must not be empty
uint64_t pts = frame_meta->pts;
state->frame_meta_queue = frame_meta->next; // remove the item
frame_meta_delete(frame_meta);
return pts;
}
static int read_packet_with_meta(void *opaque, uint8_t *buf, int buf_size) {
struct stream *stream = opaque;
struct receiver_state *state = &stream->receiver_state;
// The video stream contains raw packets, without time information. When we
// record, we retrieve the timestamps separately, from a "meta" header
// added by the server before each raw packet.
//
// The "meta" header length is 12 bytes:
// [. . . . . . . .|. . . .]. . . . . . . . . . . . . . . ...
// <-------------> <-----> <-----------------------------...
// PTS packet raw packet
// size
//
// It is followed by <packet_size> bytes containing the packet/frame.
if (!state->remaining) {
#define HEADER_SIZE 12
uint8_t header[HEADER_SIZE];
ssize_t r = net_recv_all(stream->socket, header, HEADER_SIZE);
if (r == -1) {
return AVERROR(errno);
}
if (r == 0) {
return AVERROR_EOF;
}
// no partial read (net_recv_all())
SDL_assert_release(r == HEADER_SIZE);
uint64_t pts = buffer_read64be(header);
state->remaining = buffer_read32be(&header[8]);
if (pts != NO_PTS && !receiver_state_push_meta(state, pts)) {
LOGE("Could not store PTS for recording");
// we cannot save the PTS, the recording would be broken
return AVERROR(ENOMEM);
}
}
SDL_assert(state->remaining);
if (buf_size > state->remaining) {
buf_size = state->remaining;
}
ssize_t r = net_recv(stream->socket, buf, buf_size);
if (r == -1) {
return AVERROR(errno);
}
if (r == 0) {
return AVERROR_EOF;
}
SDL_assert(state->remaining >= r);
state->remaining -= r;
return r;
}
static int read_raw_packet(void *opaque, uint8_t *buf, int buf_size) {
struct stream *stream = opaque;
ssize_t r = net_recv(stream->socket, buf, buf_size);
if (r == -1) {
return AVERROR(errno);
}
if (r == 0) {
return AVERROR_EOF;
}
return r;
}
static void notify_stopped(void) {
SDL_Event stop_event;
stop_event.type = EVENT_STREAM_STOPPED;
SDL_PushEvent(&stop_event);
}
static int run_stream(void *data) {
struct stream *stream = data;
AVFormatContext *format_ctx = avformat_alloc_context();
if (!format_ctx) {
LOGC("Could not allocate format context");
goto end;
}
unsigned char *buffer = av_malloc(BUFSIZE);
if (!buffer) {
LOGC("Could not allocate buffer");
goto finally_free_format_ctx;
}
// initialize the receiver state
stream->receiver_state.frame_meta_queue = NULL;
stream->receiver_state.remaining = 0;
// if recording is enabled, a "header" is sent between raw packets
int (*read_packet)(void *, uint8_t *, int) =
stream->recorder ? read_packet_with_meta : read_raw_packet;
AVIOContext *avio_ctx = avio_alloc_context(buffer, BUFSIZE, 0, stream,
read_packet, NULL, NULL);
if (!avio_ctx) {
LOGC("Could not allocate avio context");
// avformat_open_input takes ownership of 'buffer'
// so only free the buffer before avformat_open_input()
av_free(buffer);
goto finally_free_format_ctx;
}
format_ctx->pb = avio_ctx;
if (avformat_open_input(&format_ctx, NULL, NULL, NULL) < 0) {
LOGE("Could not open video stream");
goto finally_free_avio_ctx;
}
AVCodec *codec = avcodec_find_decoder(AV_CODEC_ID_H264);
if (!codec) {
LOGE("H.264 decoder not found");
goto end;
}
if (stream->decoder && !decoder_open(stream->decoder, codec)) {
LOGE("Could not open decoder");
goto finally_close_input;
}
if (stream->recorder && !recorder_open(stream->recorder, codec)) {
LOGE("Could not open recorder");
goto finally_close_input;
}
AVPacket packet;
av_init_packet(&packet);
packet.data = NULL;
packet.size = 0;
while (!av_read_frame(format_ctx, &packet)) {
if (stream->decoder && !decoder_push(stream->decoder, &packet)) {
av_packet_unref(&packet);
goto quit;
}
if (stream->recorder) {
// we retrieve the PTS in order they were received, so they will
// be assigned to the correct frame
Uint64 pts = receiver_state_take_meta(&stream->receiver_state);
packet.pts = pts;
packet.dts = pts;
// no need to rescale with av_packet_rescale_ts(), the timestamps
// are in microseconds both in input and output
if (!recorder_write(stream->recorder, &packet)) {
LOGE("Could not write frame to output file");
av_packet_unref(&packet);
goto quit;
}
}
av_packet_unref(&packet);
if (avio_ctx->eof_reached) {
break;
}
}
LOGD("End of frames");
quit:
if (stream->recorder) {
recorder_close(stream->recorder);
}
finally_close_input:
avformat_close_input(&format_ctx);
finally_free_avio_ctx:
av_free(avio_ctx->buffer);
av_free(avio_ctx);
finally_free_format_ctx:
avformat_free_context(format_ctx);
end:
notify_stopped();
return 0;
}
void stream_init(struct stream *stream, socket_t socket,
struct decoder *decoder, struct recorder *recorder) {
stream->socket = socket;
stream->decoder = decoder,
stream->recorder = recorder;
}
SDL_bool stream_start(struct stream *stream) {
LOGD("Starting stream thread");
stream->thread = SDL_CreateThread(run_stream, "stream", stream);
if (!stream->thread) {
LOGC("Could not start stream thread");
return SDL_FALSE;
}
return SDL_TRUE;
}
void stream_stop(struct stream *stream) {
if (stream->decoder) {
decoder_interrupt(stream->decoder);
}
}
void stream_join(struct stream *stream) {
SDL_WaitThread(stream->thread, NULL);
}