Archive:Kdenlive/Manual/Project Menu/Render/da

Information

• How to choose the correct output format and bit rate?
• What to do for rendering lossless, for an iPhone, or whatever? (Dropdown containing targets like lossless/HQ/player)

Rendering

Rendering er den proces, hvor de redigerede klip gemmes som et enkelt, færdigt videoklip. Under renderingsprocessen kan videoen blive kompromeret og konverteret til et antal forskellige videoformater (også kendt som codecs).

Renderingsdialogen bringes frem ved at klikke på rendérknappen , ved at vælge Rendér i Menuen Projekt eller ved at bruge tastaturgenvejen Ctrl + Enter.

Kategorier af renderingsprofiler

Kdenlive har mange forskellige foruddefinerede profiler at vælge iblandt. Renderingsprofilerne er grupperede i kategorier. Se billedet herunder.

Filrendering

The following figures show the render dialog when the Destination category is File Rendering. The first two figures show the layout of the dialog under ver 0.9.10 of Kdenlive and the third figure shows how the dialog appears in ver 0.9.8 of Kdenlive.

Version 0.9.10 of Kdenlive changes the render dialog significantly because it implements a method where you can choose to render the project with either a variable video bitrate (VBR) or a constant video bitrate (CBR)

Variable Bit Rate

File rendering dialog Variable Bit Rate - ver 0.9.10

When a variable bitrate profile is selected, the File Size section displays a drop down for choosing the Video quality you want. This quality figure is a codec-dependent number representing the quality of the video that will be rendered. Generally, lower numbers mean higher quality video and larger file sizes (e.g. x264, MPEG2, VPx), but some codecs use opposite order (e.g. Theora). Profiles provided with Kdenlive offer these numbers ordered from best quality (almost lossless) to lower quality (still not degrading too much). The exact file size that is produced can not be predicted when using the VBR method. The idea behind this is that you specify a certain quality of video that you want through the entire video and the encoding optimizes bitrate to give you that constant quality, lowering data size for low action scenes and using more bits for high action scenes.

Example: 1min 55 seconds of 720 x 576 H.264 iPhone footage rendered at quality 15 with the H.264/AAC High Profile would produce a file size of 186 Mb. Whereas rendering the same footage at quality quality 20 produced an 83Mb file.

Constant Bit Rate

File rendering dialog Constant Bit Rate - ver 0.9.10

When a constant bitrate (CBR) profile is selected, the File Size section displays a drop down for choosing the Video bitrate you want. This is similar to the ver <=0.9.8 behaviour of Kdenlive. You select the video bitrate you want and the video is encoded at that video bitrate across its entire length.

File rendering dialog - ver 0.9.8

DVD-rendering

DVD-rendering producerer filer, som er kompatible med programmer til lave DVD'er. MPEG2-filer oprettet med profiler til filrendering har mindre chance for at være kompatible med DVD-programmer.

Bemærk, at denne funktion ikke opretter et DVD-filsystem. Den laver blot DVD-kompatible MPEG2-filer, som kan bruges med programmer til at lave DVD'er. Hvis du markerer tilvalget Åben DVD-guide efter generering, så åbnes DVD-guiden, som du kan bruge til at oprette et DVD-filsystem (i .ISO-format). DVD-guiden kan også åbnes fra Menuen Fil.

Opret kapitelfil baseret på hjælpelinjer aktiverer kapitelmarkeringer på din DVD. Kapitler fungerer sammen med DVD-afspillerens "næste"- og "forrige"-knap, og du kan opbygge menuer til at vælge scener. For at oprette kapitler skal du bruge hjælpelinjer i projektets tidslinje til at markere hvert kapitel.

Websteder

Mobile enheder

Opret tilpassede renderingsprofiler

Du kan oprette dine egne tilpassede renderingsprofiler ved at klikke på knappen, som er fremhævet i skærmbilledet herunder

Dette vil åbne dialogen Gem profil (også vist i ovenstående skærmbillede)og feltet Parametre vil være udfyldt med renderingsparametrene for den profil, som var markeret da du klikkede på knappen . Du kan redigere parametrenes værdier og gemme din egen tilpassede renderingsprofil.

Parametrene i renderingsprofiler er "melt"-parametre. Tjek melts dokumentation for en forklaring af deres betydning eller skriv melt -help i en kommandolinje.

The above screenshot shows the Save Profile dialog as it appears in vers <=0.9.4 of Kdenlive.

In version >=0.9.5 there is an improved version of the Save Profile dialog (see below) which allows you to customize the bitrates that are offered in the render profile.

Se også Parametre til renderingsprofiler - hvordan de læses

Rendering i batchtilstand

Hvis du har mange opgaver, der skal renderes, så kan du bruge Kdenlive til at oprette renderingsscripts, som du kan samle sammen og udføre i batchtilstand i løbet af natten. Se Rendering med brug af renderingsscripts.

Du kan også starte renderingen af et projekt, og når det er begyndt at køre i Job køen kan du trække renderingsvinduet ud af syne og fortsætte med at redigere projektet eller indlæse et nyt projekt og også rendere det. Det næste startede renderingsjob vil komme i Job køen. Redigerer du et projekt efter at renderingsjobbet er lagt i køen, så påvirker det ikke dette renderingsjob.

Rendering med brug af hjælpelinjer

Dette gør brug af hjælpelinjer til at definere et område af projektet, som skal renderes. Se Rendering ved brug af hjælpelinjer og renderingsscripts.

Rendering ved brug af tilvalget Valgt zone

Hvis du aktiverer radioknappen Valgt zone nederst i renderingsdialogen, så vil Kdenlive kun rendere den del af projektet, som er inkluderet i en markeret zone. Se Opret zoner i projektmonitoren

Render Overlay

This option overlays a time code or frame count over the rendered video. This will put the overlay over the entire rendered project. Alternatively you can use the Dynamic Text effect to overlay selected regions of the video.

render overlay result

Export Metadata

Check this to have the metadata which has been entered under Project Settings- > Metadata placed into the metadata of the rendered file.

In version 0.9.6 for Linux, you have to double-click the data area of a metadata field line to make the field available for input.

This image shows metadata settings for a project:

And this is the metadata on the resulting clip (rendered with Export Metadata checked).

$ ffprobe dog_rotated_meta_data.mp4

Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    title           : Bailey
    encoder         : Lavf53.21.1
    copyright       : VSF

Dette viser en fejl i v. 0.9.4 af Kdenlive — den fulde titel bliver ikke indført i metadata — den afskæres ved det første mellemrum. Dette er blevet rettet i v. 0.9.5 af Kdenlive som Mantis nr. 2996.

Export Audio Checkbox

This is an unusual one. Instead of a normal on/off checkbox toggle, the Export Audio checkbox cycles among three choices.

As if that weren't confusing enough, the Export audio (automatic) option may appear different depending on your combination of distribution, desktop environment and theme. See three examples below:

Regardless of how the checkbox on the Export audio (automatic) option may appear on your installation, rest assured that when that option is showing, it is enabled.

So what do the three options mean?

Export audio (automatic) means detect if an audio track is present and write the audio track if found

Export audio, when checked, means write an audio track in the rendered file even if there is no audio track to write.

Export audio, when unchecked, means do not write an audio track in the rendered file.

The difference in behavior between enabling Export audio versus Export audio (automatic) can be seen in the situation where you have a video on the timeline but there is no audio track on the timeline and the video in the video track also does not have an audio track. An example of such a situation is shown in the screenshot below.

In this situation, if you render with Enable audio (automatic), the rendered file will not have an audio track (Result 1 on screenshot below). But if you render with Export Audio checked, then the rendered file will contain an audio track — the track will however be empty (Result 2 on screenshot below).

FFprobe on file generated from an audio-less track using Export audio (automatic). Note only one stream — Stream #0.0 — a video stream. Kdenlive automatically detected there was not an audio track and so it did not write one.

$ ffprobe dog_rotated_exp_audio_auto.mp4

Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf53.21.1
Duration: 00:00:03.62, start: 0.000000, bitrate: 12592 kb/s
Stream #0.0(und): Video: h264 (High), yuv420p, 1280x720 [PAR 1:1 DAR 16:9], 12587 kb/s, 27.83 fps, 27.83 tbr, 30k tbn, 55.66 tbc

FFprobe on file generated from an audio-less track using Export audio checked. Note two streams — Stream #0.0 and Stream #0.1 — the latter being an aac audio track. We forced Kdenlive to write an audio track even though there was not any source audio to write.

$ ffprobe dog_rotated_exp_audio.mp4

Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf53.21.1
  Duration: 00:00:03.62, start: 0.000000, bitrate: 12598 kb/s

Stream #0.0(und): Video: h264 (High), yuv420p, 1280x720 [PAR 1:1 DAR 16:9], 12587 kb/s, 27.83 fps, 27.83 tbr, 30k tbn, 55.66 tbc
Stream #0.1(und): Audio: aac, 48000 Hz, stereo, s16, 2 kb/s

In cases where there is an audio track ...

Rendering with Export audio unchecked will produce a file with no audio track — result 4 in the screenshot above. Rendering with Export audio (automatic) (result 3 in the screenshot above) or with Export audio checked will produce files with Audio tracks.

Encoder Threads

Determines the value of Encoding threads passed to melt. For encoding to certain codecs, namely MPEG-2, MPEG-4, H.264, and VP8, kdenlive can use more than one thread and thus make use of multiple cores. Increase this number to take advantage of this feature on multi-core machines. See melt doco - threads and melt FAQ on multi-threading.

Scanning Dropdown

This option controls the frame scanning setting the rendered file will have. Options are Force Progressive, Force Interlaced and Auto.

Auto causes the rendered file to to take the scanning settings that are defined in the project settings. Use the other options to override the setting defined in the project settings.

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