Set up the source stream using FFmpeg
Use FFmpeg to generate a test source and send it to an MK.IO live event. For SRT input, use an FFmpeg binary compiled with libsrt.
RTMP basic example
Section titled “RTMP basic example”This command generates a 1080p test pattern and a 150 Hz tone. It encodes the video with H.264, encodes the audio with AAC, and sends the constant-bitrate output to an RTMP input URL.
ffmpeg -threads 0 \-re \-f lavfi \-i testsrc=rate=30:size=1920x1080,format=yuv420p \-f lavfi \ -i "sine=frequency=150:sample_rate=48000:beep_factor=2" \-c:a aac \-ab 48k \-ac 2 \-ar 48000 \-c:v libx264 \-preset:v fast \-b:v 500k \-minrate 500k -maxrate 500k -bufsize 500k \-r 30 \-g 60 -keyint_min 60 \-sc_threshold 0 \-f flv \rtmp://in-7334a7c7-a376-4edf-aeb9-d6bfd7fab995.japaneast.streaming.mediakind.com:1935/de04ea37-ace5-46e1-9a54-6cb045c424df/streamCommand breakdown
Section titled “Command breakdown”The table describes each part of the command:
| Command | Description |
|---|---|
-threads 0 | Sets the number of threads for processing. 0 lets FFmpeg decide the number of threads based on the available CPU cores. |
-re | Makes FFmpeg read input in real time rather than as fast as possible. This makes the generated input match playback speed. |
-f lavfi | Specifies the lavfi input format so FFmpeg generates input with a filter instead of reading an external file or stream. |
-i testsrc=rate=30:size=1920x1080,format=yuv420p | Generates a test pattern at 30 frames per second with a resolution of 1920x1080 and a YUV 4:2:0 pixel format. |
-f lavfi -i "sine=frequency=150:sample_rate=48000:beep_factor=2" | Generates a 150 Hz audio tone at a 48 kHz sample rate. beep_factor=2 adds breaks instead of producing a continuous tone. |
-c:a aac | Sets the audio codec to AAC, a widely used audio compression format. |
-ab 48k | Sets the audio bitrate to 48 kbps. |
-ac 2 | Sets the number of audio channels to 2 (stereo). |
-ar 48000 | Sets the audio sample rate to 48 kHz. |
-c:v libx264 | Sets the video codec to H.264 using libx264, which is efficient and compatible with most streaming platforms. |
-preset:v fast | Uses the fast libx264 encoding preset. |
-b:v 500k | Sets the target video bitrate to 500 kbps. |
-minrate 500k -maxrate 500k -bufsize 500k | Sets the minimum rate, maximum rate, and buffer size to 500 kbps for constant-bitrate output. |
-r 30 | Sets the output frame rate to 30 fps, matching the input video frame rate. |
-g 60 -keyint_min 60 | Sets the group of pictures (GOP) length and minimum keyframe interval to 60 frames. This produces a keyframe every two seconds at 30 fps. Match this value to the Input key frame interval in MK.IO. |
-sc_threshold 0 | Sets the scene change threshold to 0 so FFmpeg does not add keyframes for scene changes. This keeps the GOP structure stable. |
-f flv | Specifies the output format as flv, which is commonly used for streaming to RTMP servers. |
rtmp://... | Specifies the RTMP server URL. Paste the Input URL provided after you start the live event. |
RTMP example with multiple bitrates
Section titled “RTMP example with multiple bitrates”This example sends three video qualities to an MK.IO passthrough event. Use a unique stream name for each quality and align keyframes across all qualities.
ffmpeg.exe -threads 0 -re /-stream_loop -1 -i "C:\Videos\sample.mp4" /-c:a aac -ab 128k -ac 2 -ar 48000 -c:v libx264 -s svga -b:v 500k -minrate 500k -maxrate 500k -bufsize 500k -r 30 -g 48 -keyint_min 48 -sc_threshold 0 -f flv rtmp://in-7334a7c7-a376-4edf-aeb9-d6bfd7fab995.japaneast.streaming.mediakind.com:1935/de04ea37-ace5-46e1-9a54-6cb045c424df/stream_500 /-c:a aac -ab 128k -ac 2 -ar 48000 -c:v libx264 -s vga -b:v 300k -minrate 300k -maxrate 300k -bufsize 300k -r 30 -g 48 -keyint_min 48 -sc_threshold 0 -f flv rtmp://in-7334a7c7-a376-4edf-aeb9-d6bfd7fab995.japaneast.streaming.mediakind.com:1935/de04ea37-ace5-46e1-9a54-6cb045c424df/stream_300 /-c:a aac -ab 128k -ac 2 -ar 48000 -c:v libx264 -s qvga -b:v 150k -minrate 150k -maxrate 150k -bufsize 150k -r 30 -g 48 -keyint_min 48 -sc_threshold 0 -f flv rtmp://in-7334a7c7-a376-4edf-aeb9-d6bfd7fab995.japaneast.streaming.mediakind.com:1935/de04ea37-ace5-46e1-9a54-6cb045c424df/stream_150Adjust the encoding settings for the available CPU capacity, network bandwidth, and required output quality.