Glossary

Apple ProRes is a family of intraframe video codecs from Apple, built for editing rather than delivery, in tiers from 422 Proxy to 4444 XQ. B-ROLL converts downloads to ProRes 422 Proxy, LT, 422 or HQ in a .mov file.

Audio formats for editing range from lossy MP3 and AAC to uncompressed WAV and lossless FLAC. Converting a lossy source to WAV or FLAC avoids a second lossy step but adds no quality.

AV1 is a royalty-free long-GOP video codec from the Alliance for Open Media that YouTube uses for streaming.

A batch download is a queue of many videos started at once, for example from a text file of links or a bookmarks folder.

Bitrate is the amount of data per second of video or audio, measured in megabits or kilobits per second, and it limits how much detail a stream can hold. B-ROLL shows the real bitrate measured on each downloaded file.

"Sign in to confirm you're not a bot" is a YouTube message that stops a request until it comes from a signed-in account.

A clip or section download is a download that saves only the part of a video between a start and an end time instead of the whole video. B-ROLL names each clip "Title [mm-ss to mm-ss]".

A container is the file wrapper, such as MOV, MP4, MKV or WEBM, that holds video, audio and subtitle streams. The codec inside the container decides how editable the file is.

A cookies.txt file is a Netscape-format text export of browser cookies that lets a download tool make requests as your own signed-in account.

Creative Commons licenses are public licenses that let creators allow reuse under set conditions. YouTube lets creators mark videos with CC BY, which requires attribution.

Credits and attribution name the creator and source of footage you use, as a license, a permission or the platform expects.

A credits file is a text file that B-ROLL writes next to each download with the title, creator, channel, source link, upload date, license line and a ready credit line.

Deno is an open-source JavaScript runtime. yt-dlp uses Deno when it talks to YouTube, and B-ROLL downloads it on first launch.

DNxHR is Avid's resolution-independent family of intraframe editing codecs, in the tiers LB, SQ, HQ, HQX and 444. B-ROLL converts to DNxHR LB, SQ or HQ, and to HQX for 10-bit sources.

Fair use is a United States copyright exception for limited use of protected material, judged case by case on four factors. Other countries have narrower exceptions, such as fair dealing.

ffmpeg is a free, open-source toolkit that converts, cuts and merges audio and video. B-ROLL uses ffmpeg to merge streams, cut clips and convert to ProRes or DNxHR.

H.264, also called AVC, is a long-GOP video codec standardized jointly by the ITU-T and ISO/IEC.

HTTP Error 403 Forbidden is a server response that refuses a request. On YouTube downloads it points to an expired stream link or a rejected request.

In and out points are the marks that set where a clip starts and ends. In the B-ROLL preview player, I sets the in point and O sets the out point.

An intermediate codec is an intraframe format, such as ProRes or DNxHR, that trades larger files for smooth editing and repeated re-encoding with little visible loss.

J, K and L shuttle is the editing keyboard convention for playback: L plays forward, J plays backward and K pauses, and pressing J or L again speeds playback up.

A keyframe cut is a fast cut that snaps to the nearest keyframe, while a frame-exact cut re-encodes around the cut points so the clip starts where you asked.

Licensing is the permission, from a rights holder or through a public license, that lets you use footage someone else owns.

Long-GOP is a compression method that stores most frames as differences from nearby frames, which keeps files small but makes them heavier to scrub than intraframe codecs that store every frame whole.

Opus and AAC are lossy audio codecs, and they are the ones YouTube uses for its audio streams.

A playlist or channel download is a batch that queues many videos from one YouTube link and saves them into one folder.

A portable app is a program that runs without an installer. The B-ROLL portable exe still keeps its tools and settings in %LOCALAPPDATA%\Broll on each PC.

Proxy media are lightweight copies of original clips that an editing app plays while you cut, then swaps back for the originals at export.

Sample rate is the number of audio samples per second. Video work uses 48 kHz, while music is often released at 44.1 kHz.

A SHA-256 checksum is a 64-character fingerprint of a file. If the checksum of your download matches the one published for it, the file is the one that was published.

Microsoft Defender SmartScreen is the Windows feature that shows "Windows protected your PC" before running an app with little download reputation, such as an unsigned app.

SRT, VTT and ASS are text subtitle formats: SRT is the simplest, VTT is the web standard, and ASS adds styling and positioning.

Subtitles are timed text tracks that can be saved as separate files or embedded in a video file.

Timeline playback is how smoothly an editing app plays and scrubs a clip, which depends mostly on the codec and the computer's decoding power.

Transcoding is a conversion that re-encodes a file from one codec to another, for example from a YouTube AV1 stream to ProRes or DNxHR for editing.

VP9 is a long-GOP video codec developed by Google and used by YouTube for streaming.

yt-dlp is a free, open-source command-line program that downloads video and audio from YouTube and many other sites. B-ROLL uses yt-dlp for every download.