A guide for the author, the writers (human or model) and anyone judging a cut. Written 2026-09-20 from published advice by working trailer editors (sources at the end) and from what we learned making two Memory Road trailers. The writers' brief (TRAILER_BRIEF.md section 11a) is the enforceable short form of this; this file is the reasoning.
A trailer is an advertisement for a story, not a summary of it. Its single job is to make a stranger want the rest. Filmmaker Magazine's trailer editor puts it as selling "promise and possibility", and gives the rule that follows from it:
+"Never resolve anything! Whenever possible, leave questions unanswered."+
A film trailer is cut from the film: real scenes, real lines, reordered and compressed. A book has no footage, so we film the scenes first - but the discipline is the same. The trailer shows moments that exist in the book, in the words the author wrote, arranged to raise a question the viewer can only answer by reading it.
+The measure of success is not "did every shot work". Our second trailer passed that test and was dull. The measure is: could someone who has never heard of this book say, after one viewing, who it is about, what is wrong, what he wants, who is against him - and do they want to know what happens?
+Everything below comes from this. The viewer has not read the book, does not know a name, and will watch once. After our second trailer the owner - who knows the book - still asked: who are the two people on the sofa? who is "they"? why would they sell his car? does he have a memory problem? why is a policeman on the ground? how did a passing car become a man in a trunk?
+Each of those is a fact the writer knew and the screen never said.
+Editors describe three acts; Derek Lieu's four-part version is the more useful because it separates the hook from the setup.
+| part | share of the running time | what it must do |
|---|---|---|
| 1. Cold open | first 10-15 s | "Hit the ground running with some very exciting, humorous or dramatic scene that requires very little context." One or two shots. The book's best small moment - funny, tender or alarming. Not chapter one. |
| 2. Introduction | to about 35-40 s | The premise. By the end of it the viewer can answer who is this, what is wrong, what does he want. Slowest cutting of the trailer; shots breathe. |
| 3. Escalation | the middle | "Where the antagonist or central problem is introduced, and we get an idea of what the main characters are going to do about it." The opposition gets a face and a reason. Cutting gets quicker. |
| 4. Climax | last 20-30 s | "The music swells, the most interesting shots get cut in rapid succession." Short wordless shots, each shorter than the last (2.5 s, 2 s, 1.5 s...). Then a stop, a last line or image - the button - and the title. |
Energy should rise and fall, not sit at one level: an early quiet moment makes the later noise louder. The strongest single device in trailer sound is the stop: everything cuts to silence for half a second before the final hit or the title.
+Length. A full trailer is 1:30-2:30; a teaser is about a minute. For a book, shorter is safer: 75-100 seconds. Ours ran 2:02 with nineteen shots of nearly equal length, which is a slideshow's rhythm, not a trailer's.
+Measured on our second trailer: of 14 spoken lines, 3 were in the manuscript, 3 paraphrased it, 8 were invented by the script model. The three that landed were the author's - "Does that mean you're not trying to pick me up?" is funnier and truer than anything written for the occasion.
+So: a line spoken on camera is found in the manuscript and used as written - whole or trimmed, never reworded into something the character did not say. The site checks every on-camera line against the manuscript and marks each line on the page: your words, from the book / close to the book / written for the trailer.
+Trailer editors sort sound bites into three kinds (Lieu):
+A good trailer line works with no context. If it needs the previous page to make sense, it is the wrong line.
+"Narration handles complex exposition efficiently, allowing audiences to absorb context while watching related visuals."+
Narration and title cards interrupt the picture, so editors use them sparingly - but a book trailer has more to explain than a film trailer and no famous faces to lean on. Use one narrator, one voice, three to five lines, each laid over pictures that show what it says:
+The narrator is not the hero thinking aloud, and must say only what the book establishes. It is the voice telling a stranger why this story matters.
+Three or four words, on screen about a second, at most three of them before the viewer loses the thread. Good for time, place and the one fact a picture cannot carry: FORT LAUDERDALE, 2016. HE KNOWS TOO MUCH. And the last card is the title, after the stop.
+A trailer may skip time. It may not skip the reason. If one shot ends with a deputy shining a torch in a man's face and the next begins with the deputy on the ground, the viewer needs the cause - shown, said, or bridged by the narrator ("He had not meant to hurt anyone."). The same for a car pulling up and a man found in a trunk: show the hands, the door, the dark - or say it.
+Editors also pair sound to picture noun by noun: "Trailer editors will usually latch onto any noun in a line of dialogue, and try to find an image that will go with it." If the narrator says road, we are looking at the road.
+Music "literally sets the tone and the rhythm"; most trailers use up to three cues, one per act. We do not yet lay music - it is the largest remaining gap - but the cut should be planned for it: a quiet bed under the introduction, a pulse through the escalation, rises into hits in the climax, then the stop. One well-placed hit is powerful; "four is a parody".
+| craft rule | how we do it |
|---|---|
| On-camera lines from the book | checker objects to an on-camera line not in the manuscript; page badges every line |
| Narrator | a cast member with a voice and no appearance; all lines lip_sync: false |
| Shots run their written length, line placed within | stretched Action/Cut slate, say_at start / middle / end |
| Accelerating climax | wordless shots may be as short as 1.5 s in the edit (each still costs a 5 s generation) |
| One action too big for one take | split into two shots (the abduction became 17 and 17a) |
| Objects and cars stay the same | tracked props with reference pictures |
| The camera can actually see it | line-of-sight rule (no urn "seen" from the back seat) |
| Nothing bought twice | request-hash guard on pictures, clips and audio |