TS Format Guide

Available Conversions

About TS Format

TS (Transport Stream, also known as MPEG-TS or MPEG Transport Stream) is a protocol and container format for transmission and storage of audio, video, and data, specified in MPEG-2 Part 1 (ISO/IEC 13818-1). Unlike MPEG Program Streams (.mpg/.mpeg files), which are optimized for relatively error-free storage media like DVDs and hard drives, Transport Streams are specifically designed for communication over unreliable or error-prone transmission channels such as broadcast television, satellite links, cable networks, and internet streaming. The format employs fixed-size packets (188 bytes or 204 bytes with error correction data), extensive synchronization mechanisms, and error resilience features that enable receivers to maintain playback even when portions of the stream are corrupted or lost.

The Transport Stream architecture uses 188-byte packets (or 204-byte packets when Reed-Solomon forward error correction is added for broadcast applications) as its fundamental unit, each beginning with a sync byte (0x47) that allows receivers to identify packet boundaries even after data loss. Each packet contains a 4-byte header identifying the Packet ID (PID), which distinguishes between different elementary streams (video, audio, subtitles, program information) multiplexed within the transport stream, followed by 184 bytes of payload data. This fixed-packet structure is crucial for broadcast synchronization: transmitters and receivers can maintain timing and recover from errors without requiring bidirectional communication or retransmission, unlike file-based formats that assume perfect data integrity.

Transport Streams support multiplexing multiple programs (TV channels) within a single stream, a capability essential for digital television broadcasting where a single RF channel carries multiple standard-definition or high-definition programs simultaneously. The Program Specific Information (PSI) tables embedded in the stream—including the Program Association Table (PAT), Program Map Table (PMT), Conditional Access Table (CAT), and Network Information Table (NIT)—allow receivers to identify available programs, locate their constituent audio and video streams, and access metadata like channel names and electronic program guide (EPG) information. This multiplexing architecture enabled the dramatic expansion of channel capacity during the transition from analog to digital television in the late 1990s and 2000s, allowing broadcasters to fit 4-6 SD channels or 1-2 HD channels in the same spectrum previously occupied by a single analog channel.

While originally designed for MPEG-2 video and audio codecs, Transport Streams have evolved to support modern codecs including H.264/AVC (widely adopted for HDTV broadcasting starting in the mid-2000s), H.265/HEVC (used for 4K broadcasting), AAC audio, and newer formats like AV1. The format's flexibility and extensibility through defined descriptor mechanisms allow broadcasters to introduce new technologies while maintaining backward compatibility with existing receiver infrastructure. Today, Transport Streams remain the dominant container format for digital television worldwide (DVB in Europe, ATSC in North America, ISDB in Japan and South America), Blu-ray Disc video, and HTTP Live Streaming (HLS)—Apple's widely-adopted internet streaming protocol that segments Transport Streams into chunks for adaptive bitrate delivery over HTTP.

History of TS

Transport Stream was developed alongside the MPEG-2 standard during the early 1990s as the international community worked to define digital television systems that would replace analog broadcasting. The MPEG-2 Systems specification (ISO/IEC 13818-1), approved in November 1994 and published in 1995, defined both Program Streams (for storage) and Transport Streams (for transmission). While Program Streams inherited conceptual DNA from MPEG-1 Systems and were designed for DVD-Video and similar applications, Transport Streams represented a fundamentally different approach optimized for the harsh realities of broadcast transmission: signal interference, multipath propagation, atmospheric conditions, and the inability to request retransmission of lost data.

The first major deployment of Transport Streams came with Digital Video Broadcasting (DVB), a European consortium established in 1993 to develop standards for digital television. The DVB Project published the DVB-S (satellite) standard in 1994, DVB-C (cable) in 1994, and DVB-T (terrestrial) in 1997, all using MPEG-2 Transport Streams to deliver compressed video and audio. European digital satellite services began in 1994-1995 (Canal+ in France, BSkyB in the UK), offering dozens of channels via Transport Stream multiplexes that would have been impossible with analog transmission. DVB-T terrestrial broadcasts launched in the UK in 1998, Sweden and Spain in 1999, and progressively across Europe through the 2000s, with most countries completing analog television shutoff by 2012-2015.

North America developed the ATSC (Advanced Television Systems Committee) standard for digital television, published in December 1996. ATSC also adopted MPEG-2 Transport Streams but with different modulation schemes (8VSB for terrestrial broadcasting) tailored to the North American television landscape and spectrum allocation. ATSC broadcast transmissions began in 1998, with major U.S. cities launching digital television services that year. The United States completed its digital television transition on June 12, 2009, when all full-power analog television broadcasts ceased and Transport Stream-based ATSC became the sole over-the-air television standard. ATSC 3.0, published in 2017 and deploying in 2020s, continues using Transport Streams but adds support for HEVC/H.265 video, object-based audio, and internet-delivered content integration.

Japan developed Integrated Services Digital Broadcasting (ISDB), based on MPEG-2 Transport Streams with unique features like hierarchical transmission allowing simultaneous broadcasting of HD content to fixed receivers and SD content to mobile devices within a single Transport Stream multiplex. ISDB-T terrestrial broadcasts began in Japan in 2003, ISDB-T was subsequently adopted by most South American countries (Brazil in 2006, Argentina, Chile, Peru, and others), and Japan completed analog shutoff in 2011. The global convergence on Transport Streams for digital television—despite regional differences in modulation and features—created enormous economies of scale in receiver manufacturing and content production, solidifying MPEG-TS as the worldwide broadcast container standard.

Blu-ray Disc, developed by the Blu-ray Disc Association and launched in 2006, adopted MPEG-2 Transport Streams as its container format for video content, despite being a storage medium rather than broadcast. This decision—departing from DVD's use of Program Streams—was driven by Transport Stream's superior multiplexing flexibility, support for multiple programs (allowing special features to coexist with main content), and established infrastructure from digital television. Blu-ray streams use 192-byte source packets (188-byte Transport Stream packet plus 4 bytes of timing information), enabling precise synchronization of video, audio, and interactive features. Blu-ray's use of Transport Streams also facilitated commonality with broadcast workflows, allowing content mastered for HDTV broadcast to be repurposed for Blu-ray with minimal reprocessing.

Apple's HTTP Live Streaming (HLS), introduced in 2009 as part of iPhone OS 3.0 (later iOS 3.0), brought Transport Streams to internet streaming in an innovative way. HLS segments Transport Streams into small chunks (typically 6-10 seconds each), stores them as .ts files on web servers, and provides clients with .m3u8 playlist files listing available chunks and bitrates. Clients download chunks sequentially via standard HTTP, enabling adaptive bitrate streaming (switching between quality levels based on network conditions) without specialized streaming servers. HLS became massively successful due to iOS adoption, requiring minimal server infrastructure (just HTTP), and NAT/firewall-friendly behavior (no special ports or protocols). Today, HLS is ubiquitous in online video delivery—used by streaming services, broadcasters' catch-up services, and live event streaming—cementing Transport Stream's relevance long after many predicted container formats like MP4 would dominate.

Modern Transport Stream deployment spans an enormous range: over-the-air digital television reaching billions of viewers worldwide, satellite and cable services (DirecTV, Dish Network, Comcast, Sky, etc.), Blu-ray discs with hundreds of millions of units sold, and internet streaming via HLS (YouTube Live, Twitch, major broadcasters). While newer codecs (H.264, HEVC, AV1) have largely replaced MPEG-2 video, and newer protocols like DASH (Dynamic Adaptive Streaming over HTTP) compete with HLS, the Transport Stream container endures due to massive installed infrastructure, proven reliability over 25+ years, and flexible extensibility that accommodates new technologies without format replacement. However, for file storage and editing, users typically convert TS files to more editor-friendly containers like MP4 or MKV, driving substantial demand for TS conversion tools.

Key Features and Uses

Transport Stream packets consist of a 4-byte header and 184-byte payload (188 bytes total, or 204 bytes with Reed-Solomon FEC for broadcast). The header begins with a sync byte (0x47 in hexadecimal, 01000111 in binary), allowing receivers to identify packet boundaries by scanning for this distinctive pattern—critical for recovering synchronization after signal loss. The header also contains the Packet ID (PID), a 13-bit identifier distinguishing different elementary streams within the multiplex: video streams, multiple audio tracks (different languages or audio descriptions), subtitle streams, data services, and PSI tables. Additional header flags indicate payload priority, scrambling (encryption) status, adaptation field presence (for timing and program clock reference), and continuity counter (detecting lost packets).

The adaptation field, inserted before payload in packets requiring precise timing, carries Program Clock Reference (PCR) timestamps synchronized to a 27 MHz system clock. PCR allows receivers to reconstruct exact transmitter timing, essential for synchronizing audio and video playback and maintaining proper bitrate. Without PCR synchronization, audio/video drift would accumulate, causing lip-sync errors and buffer overflows/underflows. Transport Streams insert PCR packets frequently (typically every 40-100ms) to enable rapid receiver synchronization—critical when changing channels (receiver must lock to new stream within 1-2 seconds) or recovering from signal interruption.

Program Specific Information (PSI) tables embedded in Transport Streams describe multiplex structure and available programs. The Program Association Table (PAT), transmitted on PID 0x0000, lists all programs in the multiplex and their corresponding PMT PIDs. Each Program Map Table (PMT) describes one program's constituent streams (video PID, audio PIDs with language codes, subtitle PIDs, teletext, etc.) and their codec types. Receivers use this hierarchy to build channel lists and locate streams: scan PID 0 for PAT → read PMT PIDs → parse PMTs to find video/audio PIDs → demultiplex and decode those PIDs for playback. Service Information (SI) tables, defined by DVB and ATSC, extend PSI with electronic program guide data, channel names, current/next program information, and parental ratings.

Transport Streams support multiple programs (multiplexing), allowing a single 38 Mbps DVB-T multiplex to carry six 6 Mbps SD programs or two 15 Mbps HD programs plus metadata. Broadcasters can dynamically adjust multiplex composition—removing a program and redistributing its bitrate to others (stat-mux or statistical multiplexing)—to optimize quality for high-motion content (sports) while reducing bitrate for static content (news). This flexibility dramatically increased spectrum efficiency during the digital television transition: the same 6 MHz RF channel that carried one analog NTSC channel could carry 4-6 digital SD channels, enabling broadcasters to launch subchannels (like 5.1, 5.2, 5.3 alongside main channel 5) and expand content offerings.

Forward Error Correction (FEC) enhances Transport Stream resilience for broadcast transmission. The 204-byte packet variant adds 16 bytes of Reed-Solomon RS(204,188) error correction codes to each 188-byte packet, enabling correction of up to 8 corrupted bytes per packet—sufficient to overcome typical broadcast channel impairments like multipath interference, atmospheric noise, and signal fading. Convolutional interleaving spreads FEC data across multiple packets, protecting against burst errors (multiple consecutive lost packets). These mechanisms, combined with channel coding (OFDM modulation for DVB-T, 8VSB for ATSC), enable reliable reception even at signal levels far below what analog television required, expanding coverage areas and enabling portable/mobile reception.

File sizes for Transport Stream recordings depend on bitrate and duration, typically larger than equivalent Program Stream or MP4 files due to packet overhead and error correction data. A 1-hour HD recording from digital television at 15 Mbps video + 384 kbps audio yields approximately 6.8 GB as a Transport Stream file. The same content in MP4 container might be 6.5 GB (less overhead), while re-encoding with H.264 at equivalent quality could reduce it to 3-4 GB. Blu-ray movies at 20-30 Mbps average bitrate produce 12-20 GB Transport Stream files for a 90-minute film. HLS streaming segments are much smaller: a 10-second chunk at 5 Mbps is approximately 6 MB.

Common Applications

Digital Television Broadcasting: Transport Streams are the universal container for digital over-the-air, satellite, and cable television worldwide. DVB (Europe, Asia, Africa, Australia), ATSC (North America, South Korea), ISDB (Japan, South America), and DTMB (China) all use MPEG-2 Transport Streams to deliver video and audio to viewers. Broadcasters multiplex 4-6 SD channels or 1-2 HD channels per RF frequency, with PSI/SI tables providing electronic program guides, teletext, closed captions, and interactive services. Viewers record Transport Streams using DVRs (personal video recorders), creating .ts files stored on internal hard drives. These recordings preserve original broadcast quality and multiple audio tracks but often require conversion to MP4 or MKV for playback on devices without native Transport Stream support or for space-efficient archival.

Blu-ray Disc and AVCHD: Blu-ray Disc video uses BDAV (Blu-ray Disc Audio/Visual) Transport Streams with H.264 or VC-1 video and various audio codecs (Dolby TrueHD, DTS-HD Master Audio, LPCM). Blu-ray players read .m2ts files from the BDMV/STREAM directory, demultiplex video/audio/subtitle streams, and synchronize playback using PCR timing. AVCHD (Advanced Video Codec High Definition), a consumer camcorder format developed by Sony and Panasonic, also uses Transport Streams with H.264 video, recording to memory cards, hard drives, or DVD media. Users transferring AVCHD footage to computers for editing typically convert .mts files to MOV, MP4, or intermediate codecs (ProRes, DNxHD) because video editing software handles these formats more efficiently than Transport Streams.

HLS Streaming and Internet Video Delivery: Apple's HTTP Live Streaming segments Transport Streams into small chunks (.ts files) for adaptive bitrate streaming over HTTP. Content providers encode video at multiple bitrates (e.g., 500 kbps, 1.5 Mbps, 3 Mbps, 5 Mbps for mobile to desktop), segment each variant into 6-10 second Transport Stream chunks, and generate .m3u8 playlists indexing available chunks. Clients (iOS devices, Safari browser, VLC, video.js-based web players) download playlists, select appropriate bitrate based on network speed, and fetch .ts chunks sequentially, switching quality levels in response to bandwidth changes. HLS dominates live streaming (sports, news, events) and powers major services' video delivery, making Transport Stream chunks ubiquitous in CDN infrastructure despite end-users rarely interacting with .ts files directly.

Professional Broadcasting Workflows: Television studios, broadcast networks, and post-production facilities exchange content as Transport Streams for compatibility with broadcast infrastructure. Master Control systems ingest Transport Streams from satellite feeds, playout servers, and live production, multiplex programs with PSI/SI metadata, insert advertisements, and output modulated RF signals for transmission. Contribution feeds (sending content from remote locations to broadcast centers) use Transport Streams over satellite, fiber, or IP networks (SMPTE ST 2022, ST 2110). Archival systems preserve broadcast recordings as Transport Streams to maintain original quality, multiple audio tracks, and metadata, though long-term archives increasingly transcode to H.264/HEVC in MP4/MKV for storage efficiency.

IPTV and Streaming Services: Internet Protocol Television (IPTV) services delivered by telecommunications providers (Verizon FiOS, AT&T U-verse, BT Vision) distribute live TV channels as multicast Transport Streams over managed IP networks. Set-top boxes join multicast groups for selected channels, receive Transport Stream packets via UDP/RTP, and decode for television display. Unlike internet streaming (HLS/DASH), IPTV uses dedicated network capacity with QoS guarantees, delivering Transport Streams at consistent bitrates without adaptive streaming. Some OTT (over-the-top) services also use Transport Streams internally before packaging for HTTP delivery, leveraging broadcast-proven infrastructure and workflows.

Video Capture and Recording Devices: Capture cards and USB TV tuners receiving digital television signals save recordings as .ts files, preserving original broadcast Transport Streams without re-encoding. Users accumulating libraries of recorded broadcast content (series, movies, sports events) often convert these files to MP4 with H.264 or H.265 to reduce file sizes (50-70% reduction is common) and improve compatibility with media players, tablets, and smartphones. TS-to-MP4 conversion is one of the most common video format conversion tasks for home users managing DVR recordings.

Legacy Content and Format Conversion: Organizations with archives of Transport Stream recordings from digital television's early years (late 1990s-2000s) often convert to modern formats for preservation and accessibility. Early Transport Streams used MPEG-2 video at relatively high bitrates (8-15 Mbps for HD) that are inefficient by today's standards; transcoding to H.264 at 3-5 Mbps or HEVC at 1.5-3 Mbps preserves quality while dramatically reducing storage costs. Similarly, individuals with personal video archives from broadcast recordings, Blu-ray rips, or AVCHD camcorders convert Transport Streams to MP4 or MKV for organization in media library software (Plex, Kodi, Emby) and streaming to household devices.

Advantages and Disadvantages