FFMPEG DOWNLOAD SEGMENTS SOFTWARE

S specifies video size which can be in the form of “width x height” or the name of a size abbreviationī:v specifies a target video bitrate, which is most useful for streaming when there are bandwidth targets and requirements there is a companion b:a for audio No-scenecut is used to disable scene change detection Here, IDR interval should be 2 * your desired FPS, so 720p60 would yield an IDR interval of 120 while 720p30 would require an IDR interval of 60. X264opts specifies libx264 specific options. Some of these are described in greater detail belowĬ:v specifies the video codec to use, in our case, libx264 m3u8Īll parameters surrounded by ‘’ require inputs from the user. Here we set all of their Instantaneous Decoding Refresh ( IDR) intervals to 2 seconds and turn off the scene change detection, thus allowing the output HLS segments of all variants are perfectly time aligned, which is required by the HLS standard.įfmpeg -i -c:v libx264 -x264opts keyint= :no-scenecut -s -r -b:v -profile:v -c:a aac -sws_flags -hls_list_size. One solution is to run 4 independent instances of FFmpeg, each of them processing one variant. Suppose we are receiving the most widely used video compression standard of H.264 in RTMP at 6mbps and 1080p60 (resolution of 1920 by 1080 with a frame rate of 60 frames per second). It is widely deployed by cloud encoding services for file transcoding and can also be used for live stream transmuxing and transcoding.

FFMPEG DOWNLOAD SEGMENTS SOFTWARE

Why Twitch builds its own in-house transcoder software stack.įFmpeg ( ) is a popular open-source software project, designed to record, process and stream video and audio. What features FFmpeg doesn’t provide, and How FFmpeg satisfies most of the live transcoding requirements, These variants have different bitrates so that viewers with different levels of download bandwidth are able to consume live video streams at the best possible quality for their connection.įigure 2 depicts the input and output of the transcoder module in our live video CDN. Within the live stream processing pipeline, the transcoder module is in charge of converting an incoming RTMP stream into the HLS format with multiple variants (e.g., 1080p, 720p, etc.). To then scale our live stream content to countless viewers, Twitch uses HTTP Live Streaming ( HLS), an HTTP-based media streaming communications protocol that most video websites also use. RTMP is a protocol designed to stream video and audio on the Internet, and is mainly used for point to point communication.

Twitch, like many other live streaming services, receives live stream uploads in Real-Time Messaging Protocol ( RTMP) from its broadcasters. At its peak, Twitch ingests tens of thousands of concurrent live video streams and delivers them to viewers across the world.įigure 1 depicts the architecture of our live video Content Delivery Network (CDN) which delivers tens of thousands of concurrent live streams internationally. Every month, more than 2.2 million unique content creators stream or upload video on our website. Twitch is the world’s leading live streaming platform for video games, esports, and other emerging creative content. Please read part 2 after finishing this article. Note: This is the first part of a 2-part series. By: Jeff Gong, Software Engineer, Sahil Dhanju, Software Engineer Intern Chih-Chiang Lu, Senior Software Engineer, Yueshi Shen, Principal Research Engineer, thanks go to Christopher Kennedy, Staff Video Engineer at Crunchyroll/Ellation John Nichols, Principal Software Engineer at Xilinx, for their information on FFmpeg and reviewing this article.

Ffmpeg download segments