Output parameters after transcoding: codecs, bitrate, frame rate

After transcoding, Gcore Streaming delivers Live and VOD content in adaptive bitrate (ABR) over standard HTTP streaming protocols. The output codec, bitrate ladder, and segment format depend on the content type, target devices, and quality tier.

​

Default transcoding output

By default, the encoding stage produces H.264 video with AAC audio — the broadest compatibility profile across browsers, mobile devices, Smart TVs, set-top boxes, and players. Default output:

• Video: H.264, 30 FPS, adaptive bitrate (ABR)
• Audio: AAC, 44.1 kHz, stereo

Premium encoding adds more efficient codecs — HEVC, AV1, and VP9 — for large VOD libraries, premium-quality catalogs, and bandwidth-sensitive workflows. The Customize the output section below covers available settings and activation.

​

ABR quality ladder

The table below shows the default H.264 output resolutions and bitrates after transcoding. *To enable these qualities, contact support. The values apply to 16:9 horizontal video. For vertical video, reverse the resolution dimensions — a (1280×720) horizontal corresponds to (720×1280) vertical. Gcore uses variable bitrate (VBR) encoding. The table shows average values. The Gcore Customer Portal displays a combined audio and video bitrate.

​

Output protocols

These ABR renditions are delivered in four HTTP streaming formats: HLS MPEG-TS, HLS CMAF, MPEG-DASH, and MP4. Select the format that matches the target players, devices, latency goals, and codec requirements. For VOD, these protocols deliver adaptive bitrate playback from uploaded and transcoded videos. For Live, they deliver adaptive bitrate playback of an ongoing broadcast with regular or low latency.

​

HLS MPEG-TS

HLS MPEG-TS is the traditional HLS format that uses .ts segments. It is the safest compatibility option for Live and VOD playback, especially on older devices, set-top boxes, Smart TVs, and legacy players.

• Segment format: MPEG-TS (.ts)
• Best for: Maximum compatibility and H.264 fallback playback
• Live latency: Regular latency, usually higher than low-latency CMAF workflows
• VOD usage: Reliable HLS playback for broadly compatible H.264 renditions
• Codec fit: H.264 with AAC audio
• Example manifest:
  #EXTM3U
  #EXT-X-VERSION:3
  #EXT-X-TARGETDURATION:4
  #EXT-X-MEDIA-SEQUENCE:0
  #EXTINF:4.000,
  segment0.ts
  

​

HLS CMAF

HLS CMAF uses fragmented MP4 (.m4s) chunks. It is recommended for modern HLS playback and is required when HLS needs to carry HEVC or AV1 codecs. For Live, CMAF can also be used for low-latency playback.

• Segment format: Fragmented MP4 (.m4s)
• Best for: Modern HLS playback, Apple devices, HEVC and AV1 delivery, and low-latency Live
• Live latency: Low latency when configured with partial segments
• VOD usage: Modern HLS playback for H.264, HEVC, and AV1 renditions
• Codec fit: H.264, HEVC, AV1, and AAC audio
• Example manifest:
  #EXTM3U
  #EXT-X-VERSION:6
  #EXT-X-TARGETDURATION:2
  #EXT-X-PART-INF:PART-TARGET=0.5
  #EXTINF:2.0,
  seg0.m4s
  #EXT-X-PART:DURATION=0.5,URI="seg1_part_0.m4s",INDEPENDENT=YES
  

​

MPEG-DASH

MPEG-DASH is widely used for Android, web players, Smart TVs, and advanced player workflows. It can be used for both VOD and Live, including low-latency Live. DASH commonly uses fragmented MP4 (.m4s) chunks, and can also be used with WebM chunks for VP9 workflows.

• Segment format: Fragmented MP4 (.m4s) or WebM chunks, depending on codec and workflow
• Best for: Android, web players, Smart TVs, multi-codec VOD, and low-latency Live
• Live latency: Low latency when configured with short segments and chunked delivery
• VOD usage: Adaptive bitrate playback with H.264, HEVC, AV1, or VP9
• Codec fit: H.264, HEVC, AV1, VP9, and AAC audio
• Example MPD structure:
  <MPD type="dynamic" minimumUpdatePeriod="PT2S">
    <Period>
      <AdaptationSet>
        <SegmentTemplate media="segment_$Time$.m4s" initialization="init.mp4" duration="2000" startNumber="1">
          <SegmentTimeline>
            <S t="0" d="2000" r="4"/>
          </SegmentTimeline>
        </SegmentTemplate>
      </AdaptationSet>
    </Period>
  </MPD>
  

​

Customize the output

Default presets cover most deployments. For requirements outside the defaults, Gcore can configure custom output settings — contact support to enable them. Available customizations: Codecs and renditions

• Premium codecs: H.265/HEVC, VP9, AV1, or mixed-codec outputs
• Remove unnecessary renditions to reduce CDN costs

Resolutions and bitrate

• Higher or lower bitrate targets
• Different ABR ladders for specific devices or regions
• Add 8K quality
• Add super-low 144p quality
• Change quality presets for all or selected renditions

Frame rate

• 60+ FPS or original FPS passthrough

Audio

• Higher audio quality; 48 kHz sample rate
• Dolby Digital, Dolby Atmos

Delivery

• Transmux VOD MP4 files to HLS on the fly
• Pass-through instead of transcoding for Live streams

High-resolution (2K/4K+) and premium codec settings are not included in the basic plan. Costs are listed on the pricing page. Each video can have its own configuration. Default and custom presets work together for per-stream or per-library tuning. Available quality sets are listed in the quality sets API.

​

Output examples

The examples below show the output formats and codec combinations described above for VOD and Live playback.

​

VOD: multi-codec

This video contains AV1, VP9, HEVC, and H.264 renditions, AAC audio, and English subtitles. Note that while Firefox handles VP9 playback successfully, Chrome currently does not support it for this stream. Video qualities include 360p, 468p, 720p, 1080p, and 4K variants. Playback URLs:

• HTML player
• HLS manifest
• MPEG-DASH manifest

​

Live: 1080p H.264

The embedded player shows live stream playback for Gcore output protocols. Playback URLs:

• HTML player
• MPEG-DASH CMAF (low latency)
• LL HLS CMAF (low latency)
• HLS MPEG-TS (regular latency)