To start separate FFmpeg outputs at different positions in their source videos, put a separate -ss seek before each input’s -i. Use -itsoffset only when you want to shift timestamps, not choose a different scene or song. FFmpeg options are order-sensitive: they generally apply to the next input or output file.
Choose what “different start times” means
There are several distinct timing tasks that can sound alike. Choose the one that matches your intended result before changing the command.
As an Amazon Associate I earn from qualifying purchases.
| Goal | Use | What it changes |
|---|---|---|
| Begin each source at a different scene or song | -ss before that source’s -i |
The media position selected from that input. |
| Delay or advance an input’s timestamps | -itsoffset before that input’s -i |
Timestamps for that input’s streams, not the content position. |
| Begin reading at a segment in a live HLS playlist | HLS demuxer options such as live_start_index |
The segment index selected from the incoming live playlist. |
| Produce multiple quality variants of one presentation | Stream mapping and var_stream_map |
Renditions of the presentation, not independent start schedules. |
These approaches solve different problems; a timestamp delay is not a substitute for seeking into a recording.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Seek each independent input to its own position
Put each -ss immediately before the corresponding -i. The following schematic command maps optional video and audio from two inputs to two outputs. It illustrates option scope and mapping; it is not a tested, ready-to-publish YouTube command. Replace output destinations and codec settings to match your ingest protocol.
#1 Best Overall
- HD streaming made simple: With America’s number 1 TV streaming platform,* exploring popular apps—plus tons of free movies, shows, and live TV—is as easy as it is fun. *Based on hours streamed—Hypothesis Group
- Compact without compromises: The sleek design of Roku Streaming Stick won’t block neighboring HDMI ports, and it even powers from your TV alone, plugging into the back and staying out of sight. No wall outlet, no extra cords, no clutter.
- No more juggling remotes: Power up your TV, adjust the volume, and control your Roku device with one remote. Use your voice to quickly search, play entertainment, and more.
- Shows on the go: Take your TV to-go when traveling—without needing to log into someone else’s device.
- TV, simplified: With setup that only takes minutes, a simple-to-navigate Home Screen, and an uncluttered remote control that does all you need—Roku makes it easier to watch the TV you love.
ffmpeg
-ss 00:02:00 -i inputA.mp4
-map 0:v? -map 0:a? -c:v libx264 -c:a aac OUTPUT_A
-ss 00:05:00 -i inputB.mp4
-map 1:v? -map 1:a? -c:v libx264 -c:a aac OUTPUT_BHere, input A is sought to 2:00 and input B to 5:00. Because the options are placed before their respective inputs, each seek applies to the intended source. Mapping labels each input by its position in the command: 0 for the first and 1 for the second. The question mark makes each selected stream type optional, so the command does not require both video and audio to exist in every input.
Option placement matters
FFmpeg options generally apply to the next input or output file and reset between files. Keep each input option beside the input it is meant to affect; do not assume one -ss will also govern later inputs. The documented output-side form of -ss instead decodes and discards input until the requested position. For per-input starts, use the input-side placement shown above. See FFmpeg’s main options documentation.
Rank #2
- Ultra-speedy streaming: Roku Ultra is 30% faster than any other Roku player, delivering a lightning-fast interface and apps that launch in a snap.
- Cinematic streaming: This TV streaming device brings the movie theater to your living room with spectacular 4K, HDR10+, and Dolby Vision picture alongside immersive Dolby Atmos audio.
- The ultimate Roku remote: The rechargeable Roku Voice Remote Pro offers backlit buttons, hands-free voice controls, and a lost remote finder.
- No more fumbling in the dark: See what you’re pressing with backlit buttons.
- Say goodbye to batteries: Keep your remote powered for months on a single charge.
Use -itsoffset for timestamp alignment
-itsoffset is an input option that adds an offset to the input’s timestamps. A positive offset delays the corresponding streams. Place it before the input it applies to, for example: -itsoffset 00:00:10 -i inputA.mp4. This shifts timestamps; it does not make the input begin at a later scene or song. For a different content position, use -ss.
Quick wins for a faster PC:
Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Consult the FFmpeg advanced options documentation for the option definition and syntax.
Rank #3
- Stunning 4K and Dolby Vision streaming made simple: With America’s number 1 TV streaming platform,* exploring popular apps—plus tons of free movies, shows, and live TV—is as easy as it is fun. *Based on hours streamed—Hypothesis Group
- Breathtaking picture quality: Stunningly sharp 4K picture brings out rich detail in your entertainment with four times the resolution of HD. Watch as colors pop off your screen and enjoy lifelike clarity with Dolby Vision and HDR10+.
- Seamless streaming for any room: With Roku Streaming Stick 4K, watch your favorite entertainment on any TV in the house, even in rooms farther from your router thanks to the long-range Wi-Fi receiver.
- Shows on the go: Take your TV to-go when traveling—without needing to log into someone else’s device.
- Compact without compromises: Our sleek design won’t block neighboring HDMI ports, so you can switch from streaming to gaming with ease. Plus, it’s designed to stay hidden behind your TV, keeping wires neatly out of sight
Do not confuse HLS variants with separate broadcasts
If you are creating multiple HLS quality variants, FFmpeg uses stream maps and var_stream_map. When producing two or more variants, the output filename pattern must include %v so FFmpeg can distinguish the variant outputs. Those variant playlists describe renditions of a presentation; they do not, by themselves, make separate broadcasts start at different content positions.
See FFmpeg’s HLS variant stream mapping documentation. If your goal is two independent streams with different starts, configure independent inputs and outputs rather than treating variant playlists as separate schedules.
Rank #4
- Advanced 4K streaming - Elevate your entertainment with the next generation of our best-selling 4K stick, with improved streaming performance optimized for 4K TVs.
- The newest Fire TV experience (2026) – Our biggest update to Fire TV has a new, modern design that gets you to your entertainment fast. Browse dedicated content categories, pin more of your favorite apps, and get personalized recommendations from Alexa+. Spend less time scrolling, and more time watching.
- Cloud gaming, no console required – Stream Call of Duty: Black Ops 7, Hogwarts Legacy, Outer Worlds 2, Ninja Gaiden 4, and hundreds of games on your Fire TV Stick 4K Select with Xbox Game Pass and Luna via cloud gaming. Xbox Game Pass subscription and compatible controller required. Each sold separately.
- Smarter picks with Alexa+ – Getting to what you love has never been easier. Press the voice remote button and talk naturally to find what to watch across your apps, manage your smart home, or dive into virtually any topic.
- Wi-Fi 6 support - Enjoy smooth 4K streaming, even when other devices are connected to your router.
For an incoming live HLS playlist, select a segment
When the input itself is a live HLS playlist, the HLS demuxer documents live_start_index for choosing the starting segment index; negative indices count from the end of the playlist. Its prefer_x_start option can prefer an #EXT-X-START tag in the playlist. These are input-demuxer behaviors for choosing where to begin reading a live playlist, not substitutes for seeking into ordinary local files.
Windows Errors? Fix Them Before They Spread
Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallCrashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minuteCheck the FFmpeg HLS demuxer documentation for the current option syntax.
Best Value
- Essential 4K streaming – Get everything you need to stream in brilliant 4K Ultra HD with High Dynamic Range 10+ (HDR10+).
- The newest Fire TV experience (2026) – Our biggest update to Fire TV has a new, modern design that gets you to your entertainment fast. Browse dedicated content categories, pin more of your favorite apps, and get personalized recommendations from Alexa+. Spend less time scrolling, and more time watching.
- Make your TV even smarter – Fire TV gives you instant access to a world of content, tailor-made recommendations, and Alexa, all backed by fast performance.
- All your favorite apps in one place – Experience endless entertainment with access to Prime Video, Netflix, YouTube, Disney+, Apple TV+, HBO Max, Hulu, Peacock, Paramount+, and thousands more. Easily discover what to watch from hundreds of thousands of movies and TV episodes (subscription fees may apply), including free, ad-supported content.
- Getting set up is easy – Plug in and connect to Wi-Fi for smooth streaming.
Check YouTube’s HLS ingest requirements
If you send the outputs to YouTube using HLS, the ingest configuration must meet YouTube’s documented requirements. Its setup guidance specifies:
- Transport Stream (TS) segments lasting 1–4 seconds.
- A rolling playlist with no more than five outstanding segments.
- HTTPS POST or PUT transport.
- No byte-range support.
YouTube says Ultra low-latency is turned off for HLS and that HLS has higher latency because video is sent in segments. These conditions apply to HLS ingest; confirm the current protocol and settings in Live Control Room. See YouTube’s HLS ingestion setup documentation and YouTube’s live encoder settings guidance.
Troubleshoot the timing setup
- Both inputs start at the same point: Check that each
-ssappears before its own-i, with the desired position, and that the inputs are listed in the expected order. - The start is delayed but shows the same content: You may have shifted timestamps with
-itsoffset. Use-sswhen you need a different source position. - The wrong input is mapped: Count inputs from zero in command order. The first input is
0, the second1; update each-mapaccordingly. - FFmpeg cannot make distinct variant files: For two or more HLS variants, include
%vin the output filename pattern and configure the variant mapping. - YouTube rejects or delays an HLS feed: Check the TS segment duration, outstanding-segment limit, HTTPS method, and byte-range behavior against YouTube’s HLS requirements; also verify current Live Control Room settings.
What one FFmpeg process and one stream key can establish
The option behavior described here shows how FFmpeg scopes seeks, timestamp offsets, mappings, and HLS settings. It does not establish whether YouTube permits multiple distinct broadcasts to be scheduled through one FFmpeg process and one stream key. Do not assume that the two-output example guarantees that platform-specific arrangement; verify your broadcast setup in YouTube Live Control Room.
Or let it run in the cloud
If your actual goal is to keep pre-recorded video live on YouTube around the clock, StreamNeo is a cloud alternative: upload a recording or build a playlist, add your YouTube stream key, and go live. Nothing has to stay powered on at home. Each slot streams the uploaded quality up to 4K 60fps at one flat price per slot, with automatic recovery if YouTube drops the stream. The first day is free with no card. Monthly: $9.99 per month.
Quick Recap
Learn about StreamNeo, or start your free day.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
