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#include "video.h"
#include <stdatomic.h>
#include <SDL.h>
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <pulse/pulseaudio.h>
#include <pulse/simple.h>
#include "util.h"
#include "camera.h"
struct VideoContext {
bool recording;
double start_time;
double last_frame_time;
AVFormatContext *avf_context;
AVCodecContext *video_encoder;
AVFrame *video_frame;
AVPacket *av_packet;
AVStream *video_stream;
int64_t next_video_pts;
pa_simple *pulseaudio;
};
VideoContext *video_init(void) {
VideoContext *ctx = calloc(1, sizeof(VideoContext));
return ctx;
}
bool video_start(VideoContext *ctx, const char *filename, int32_t width, int32_t height, int fps, int quality) {
if (!ctx) return false;
if (ctx->recording) {
return true;
}
video_stop(ctx);
int err = avformat_alloc_output_context2(&ctx->avf_context, NULL, NULL, filename);
if (!ctx->avf_context) {
fprintf(stderr, "error: avformat_alloc_output_context2: %s\n", av_err2str(err));
return false;
}
const AVOutputFormat *fmt = ctx->avf_context->oformat;
const AVCodec *video_codec = avcodec_find_encoder(fmt->video_codec);
if (!video_codec) {
fprintf(stderr, "couldn't find encoder for codec %s\n", avcodec_get_name(fmt->video_codec));
return false;
}
ctx->video_stream = avformat_new_stream(ctx->avf_context, NULL);
ctx->video_stream->id = 0;
ctx->video_encoder = avcodec_alloc_context3(video_codec);
if (!ctx->video_encoder) {
fprintf(stderr, "couldn't create video encoding context\n");
return false;
}
ctx->av_packet = av_packet_alloc();
if (!ctx->av_packet) {
fprintf(stderr, "couldn't allocate video packet\n");
return false;
}
ctx->video_encoder->codec_id = fmt->video_codec;
ctx->video_encoder->bit_rate = (int64_t)quality * width * height;
ctx->video_encoder->width = width;
ctx->video_encoder->height = height;
ctx->video_encoder->time_base = ctx->video_stream->time_base = (AVRational){1, fps};
ctx->video_encoder->gop_size = 12;
ctx->video_encoder->pix_fmt = AV_PIX_FMT_YUV420P;
if (ctx->avf_context->oformat->flags & AVFMT_GLOBALHEADER)
ctx->video_encoder->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
err = avcodec_open2(ctx->video_encoder, video_codec, NULL);
if (err < 0) {
fprintf(stderr, "error: avcodec_open2: %s\n", av_err2str(err));
return false;
}
err = avcodec_parameters_from_context(ctx->video_stream->codecpar, ctx->video_encoder);
if (err < 0) {
fprintf(stderr, "error: avcodec_parameters_from_context: %s\n", av_err2str(err));
return false;
}
ctx->video_frame = av_frame_alloc();
if (!ctx->video_frame) {
fprintf(stderr, "couldn't allocate video frame\n");
return false;
}
ctx->video_frame->format = AV_PIX_FMT_YUV420P;
ctx->video_frame->width = ctx->video_encoder->width;
ctx->video_frame->height = ctx->video_encoder->height;
err = av_frame_get_buffer(ctx->video_frame, 0);
if (err < 0) {
fprintf(stderr, "error: av_frame_get_buffer: %s\n", av_err2str(err));
return false;
}
// av_dump_format(state->avf_context, 0, filename, 1);
err = avio_open(&ctx->avf_context->pb, filename, AVIO_FLAG_WRITE);
if (err < 0) {
fprintf(stderr, "error: avio_open: %s\n", av_err2str(err));
return false;
}
err = avformat_write_header(ctx->avf_context, NULL);
if (err < 0) {
fprintf(stderr, "error: avformat_write_header: %s\n", av_err2str(err));
return false;
}
pa_sample_spec audio_format = {
.format = PA_SAMPLE_S16NE,
.channels = 2,
.rate = 44100
};
// NOTE: SDL2 audio capture is currently broken
// https://github.com/libsdl-org/SDL/issues/9706
// once SDL3 becomes commonplace enough, we can switch to that for capturing audio.
ctx->pulseaudio = pa_simple_new(NULL, "camlet", PA_STREAM_RECORD, NULL,
"microphone", &audio_format, NULL, NULL, &err);
if (!ctx->pulseaudio) {
fprintf(stderr, "%s", pa_strerror(err));
}
pa_simple_read(ctx->pulseaudio, (char[1]){0}, 1, &err);
ctx->recording = true;
ctx->next_video_pts = 0;
ctx->start_time = ctx->last_frame_time = get_time_double();
return true;
}
static bool write_frame(VideoContext *ctx, AVCodecContext *encoder, AVStream *stream, AVFrame *frame) {
int err = avcodec_send_frame(encoder, frame);
if (err < 0) {
fprintf(stderr, "error: avcodec_send_frame: %s\n", av_err2str(err));
return false;
}
while (true) {
err = avcodec_receive_packet(encoder, ctx->av_packet);
if (err == AVERROR(EAGAIN) || err == AVERROR_EOF) {
break;
}
if (err < 0) {
fprintf(stderr, "error: avcodec_receive_packet: %s\n", av_err2str(err));
return false;
}
ctx->av_packet->stream_index = stream->index;
av_packet_rescale_ts(ctx->av_packet, encoder->time_base, stream->time_base);
err = av_interleaved_write_frame(ctx->avf_context, ctx->av_packet);
if (err < 0) {
fprintf(stderr, "error: av_interleaved_write_frame: %s\n", av_err2str(err));
return false;
}
}
return true;
}
bool video_submit_frame(VideoContext *ctx, Camera *camera) {
if (!ctx || !camera || !ctx->recording) return false;
double curr_time = get_time_double();
double time_since_start = curr_time - ctx->start_time;
double time_since_last_frame = curr_time - ctx->last_frame_time;
ctx->last_frame_time = curr_time;
int64_t video_pts = (int64_t)(time_since_start
* ctx->video_encoder->time_base.den
/ ctx->video_encoder->time_base.num);
size_t audio_size = ctx->pulseaudio
? (size_t)(time_since_last_frame * 44100 * 2 * sizeof(int16_t))
: 0;
int err;
while (audio_size > 0 && audio_size < SIZE_MAX / 2 /* just in case time goes backwards somehow */) {
uint8_t buf[4096];
size_t n = audio_size > sizeof buf ? sizeof buf : audio_size;
if (pa_simple_read(ctx->pulseaudio, buf, n, &err) < 0) {
static atomic_flag warned = ATOMIC_FLAG_INIT;
if (!atomic_flag_test_and_set_explicit(&warned, memory_order_relaxed)) {
fprintf(stderr, "error: pa_simple_read: %s\n", pa_strerror(err));
}
break;
}
audio_size -= n;
}
if (video_pts >= ctx->next_video_pts) {
err = av_frame_make_writable(ctx->video_frame);
if (err < 0) {
fprintf(stderr, "error: av_frame_make_writable: %s\n", av_err2str(err));
return false;
}
ctx->video_frame->pts = video_pts;
camera_copy_to_av_frame(camera, ctx->video_frame);
write_frame(ctx, ctx->video_encoder, ctx->video_stream, ctx->video_frame);
ctx->next_video_pts = video_pts + 1;
}
return true;
}
bool video_is_recording(VideoContext *ctx) {
if (!ctx) return false;
return ctx->recording;
}
void video_stop(VideoContext *ctx) {
if (!ctx) return;
if (ctx->recording) {
if (ctx->pulseaudio) {
pa_simple_free(ctx->pulseaudio);
ctx->pulseaudio = NULL;
}
ctx->recording = false;
// flush video encoder
write_frame(ctx, ctx->video_encoder, ctx->video_stream, NULL);
int err = av_write_trailer(ctx->avf_context);
if (err < 0) {
fprintf(stderr, "error: av_write_trailer: %s\n", av_err2str(err));
}
avio_closep(&ctx->avf_context->pb);
}
if (ctx->video_encoder) {
avcodec_free_context(&ctx->video_encoder);
}
if (ctx->video_frame) {
av_frame_free(&ctx->video_frame);
}
if (ctx->avf_context) {
if (ctx->avf_context->pb) {
avio_closep(&ctx->avf_context->pb);
}
avformat_free_context(ctx->avf_context);
ctx->avf_context = NULL;
}
if (ctx->av_packet) {
av_packet_free(&ctx->av_packet);
}
}
void video_quit(VideoContext *ctx) {
if (!ctx) return;
video_stop(ctx);
free(ctx);
}
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