obs-studio/plugins/obs-outputs/flv-mux.c

/******************************************************************************
    Copyright (C) 2014 by Hugh Bailey <obs.jim@gmail.com>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
******************************************************************************/

#include <obs.h>
#include <stdio.h>
#include <util/dstr.h>
#include <util/array-serializer.h>
#include "flv-mux.h"
#include "obs-output-ver.h"
#include "rtmp-helpers.h"

/* TODO: FIXME: this is currently hard-coded to h264 and aac!  ..not that we'll
 * use anything else for a long time. */

//#define DEBUG_TIMESTAMPS
//#define WRITE_FLV_HEADER

#define VIDEO_HEADER_SIZE 5

static inline double encoder_bitrate(obs_encoder_t *encoder)
{
	obs_data_t *settings = obs_encoder_get_settings(encoder);
	double bitrate = obs_data_get_double(settings, "bitrate");

	obs_data_release(settings);
	return bitrate;
}

#define FLV_INFO_SIZE_OFFSET 42

void write_file_info(FILE *file, int64_t duration_ms, int64_t size)
{
	char buf[64];
	char *enc = buf;
	char *end = enc + sizeof(buf);

	fseek(file, FLV_INFO_SIZE_OFFSET, SEEK_SET);

	enc_num_val(&enc, end, "duration", (double)duration_ms / 1000.0);
	enc_num_val(&enc, end, "fileSize", (double)size);

	fwrite(buf, 1, enc - buf, file);
}

static bool build_flv_meta_data(obs_output_t *context,
		uint8_t **output, size_t *size, size_t a_idx)
{
	obs_encoder_t *vencoder = obs_output_get_video_encoder(context);
	obs_encoder_t *aencoder = obs_output_get_audio_encoder(context, a_idx);
	video_t       *video    = obs_encoder_video(vencoder);
	audio_t       *audio    = obs_encoder_audio(aencoder);
	char buf[4096];
	char *enc = buf;
	char *end = enc+sizeof(buf);
	struct dstr encoder_name = {0};

	if (a_idx > 0 && !aencoder)
		return false;

	enc_str(&enc, end, "onMetaData");

	*enc++ = AMF_ECMA_ARRAY;
	enc    = AMF_EncodeInt32(enc, end, a_idx == 0 ? 14 : 9);

	enc_num_val(&enc, end, "duration", 0.0);
	enc_num_val(&enc, end, "fileSize", 0.0);

	if (a_idx == 0) {
		enc_num_val(&enc, end, "width",
				(double)obs_encoder_get_width(vencoder));
		enc_num_val(&enc, end, "height",
				(double)obs_encoder_get_height(vencoder));

		enc_str_val(&enc, end, "videocodecid", "avc1");
		enc_num_val(&enc, end, "videodatarate",
				encoder_bitrate(vencoder));
		enc_num_val(&enc, end, "framerate",
				video_output_get_frame_rate(video));
	}

	enc_str_val(&enc, end, "audiocodecid", "mp4a");
	enc_num_val(&enc, end, "audiodatarate", encoder_bitrate(aencoder));
	enc_num_val(&enc, end, "audiosamplerate",
			(double)audio_output_get_sample_rate(audio));
	enc_num_val(&enc, end, "audiosamplesize", 16.0);
	enc_num_val(&enc, end, "audiochannels",
			(double)audio_output_get_channels(audio));

	enc_bool_val(&enc, end, "stereo",
			audio_output_get_channels(audio) == 2);

	dstr_printf(&encoder_name, "%s (libobs version ",
			MODULE_NAME);

#ifdef HAVE_OBSCONFIG_H
	dstr_cat(&encoder_name, OBS_VERSION);
#else
	dstr_catf(&encoder_name, "%d.%d.%d",
			LIBOBS_API_MAJOR_VER,
			LIBOBS_API_MINOR_VER,
			LIBOBS_API_PATCH_VER);
#endif

	dstr_cat(&encoder_name, ")");

	enc_str_val(&enc, end, "encoder", encoder_name.array);
	dstr_free(&encoder_name);

	*enc++  = 0;
	*enc++  = 0;
	*enc++  = AMF_OBJECT_END;

	*size   = enc-buf;
	*output = bmemdup(buf, *size);
	return true;
}

bool flv_meta_data(obs_output_t *context, uint8_t **output, size_t *size,
		bool write_header, size_t audio_idx)
{
	struct array_output_data data;
	struct serializer s;
	uint8_t *meta_data = NULL;
	size_t  meta_data_size;
	uint32_t start_pos;

	array_output_serializer_init(&s, &data);

	if (!build_flv_meta_data(context, &meta_data, &meta_data_size,
				audio_idx)) {
		bfree(meta_data);
		return false;
	}

	if (write_header) {
		s_write(&s, "FLV", 3);
		s_w8(&s, 1);
		s_w8(&s, 5);
		s_wb32(&s, 9);
		s_wb32(&s, 0);
	}

	start_pos = serializer_get_pos(&s);

	s_w8(&s, RTMP_PACKET_TYPE_INFO);

	s_wb24(&s, (uint32_t)meta_data_size);
	s_wb32(&s, 0);
	s_wb24(&s, 0);

	s_write(&s, meta_data, meta_data_size);

	s_wb32(&s, (uint32_t)serializer_get_pos(&s) - start_pos + 4 - 1);

	*output = data.bytes.array;
	*size   = data.bytes.num;

	bfree(meta_data);
	return true;
}

#ifdef DEBUG_TIMESTAMPS
static int32_t last_time = 0;
#endif

static void flv_video(struct serializer *s, struct encoder_packet *packet,
		bool is_header)
{
	int64_t offset  = packet->pts - packet->dts;
	int32_t time_ms = get_ms_time(packet, packet->dts);

	if (!packet->data || !packet->size)
		return;

	s_w8(s, RTMP_PACKET_TYPE_VIDEO);

#ifdef DEBUG_TIMESTAMPS
	blog(LOG_DEBUG, "Video: %lu", time_ms);

	if (last_time > time_ms)
		blog(LOG_DEBUG, "Non-monotonic");

	last_time = time_ms;
#endif

	s_wb24(s, (uint32_t)packet->size + 5);
	s_wb24(s, time_ms);
	s_w8(s, (time_ms >> 24) & 0x7F);
	s_wb24(s, 0);

	/* these are the 5 extra bytes mentioned above */
	s_w8(s, packet->keyframe ? 0x17 : 0x27);
	s_w8(s, is_header ? 0 : 1);
	s_wb24(s, get_ms_time(packet, offset));
	s_write(s, packet->data, packet->size);

	/* write tag size (starting byte doesnt count) */
	s_wb32(s, (uint32_t)serializer_get_pos(s) + 4 - 1);
}

static void flv_audio(struct serializer *s, struct encoder_packet *packet,
		bool is_header)
{
	int32_t time_ms = get_ms_time(packet, packet->dts);

	if (!packet->data || !packet->size)
		return;

	s_w8(s, RTMP_PACKET_TYPE_AUDIO);

#ifdef DEBUG_TIMESTAMPS
	blog(LOG_DEBUG, "Audio: %lu", time_ms);

	if (last_time > time_ms)
		blog(LOG_DEBUG, "Non-monotonic");

	last_time = time_ms;
#endif

	s_wb24(s, (uint32_t)packet->size + 2);
	s_wb24(s, time_ms);
	s_w8(s, (time_ms >> 24) & 0x7F);
	s_wb24(s, 0);

	/* these are the two extra bytes mentioned above */
	s_w8(s, 0xaf);
	s_w8(s, is_header ? 0 : 1);
	s_write(s, packet->data, packet->size);

	/* write tag size (starting byte doesnt count) */
	s_wb32(s, (uint32_t)serializer_get_pos(s) + 4 - 1);
}

void flv_packet_mux(struct encoder_packet *packet,
		uint8_t **output, size_t *size, bool is_header)
{
	struct array_output_data data;
	struct serializer s;

	array_output_serializer_init(&s, &data);

	if (packet->type == OBS_ENCODER_VIDEO)
		flv_video(&s, packet, is_header);
	else
		flv_audio(&s, packet, is_header);

	*output = data.bytes.array;
	*size   = data.bytes.num;
}