Saída de vídeo

Preparando o seu trabalho para criação de vídeos

Once you master the art of 3D animation, you will probably want to share your work with others; either on the Internet (YouTube, Vimeo, etc.) or with family and friends (DVD/Blu-ray) or even possibly for television broadcast.

To spare you some disappointment, here are some tips specifically targeted at video preparation.

Áreas de segurança e Super-Projeção

For anyone creating motion graphics or simple text overlays, overscan is an important consideration. Although its origins are rooted in historic analog TV systems, unfortunately even in 2017, for various reasons it can still be an issue with modern digital flat screen TVs.

Nota

Due to various limitations in analog TV equipment, the displayed image could sometimes end up shifted horizontally or vary in size, which could lead to the area beyond the intended visible picture being shown. This hidden area sometimes contained junk noise, timing signals or closed-caption/subtitle data. To avoid this being visible to the viewer, the standard approach for TV manufacturers was to “overscan” (zoom in) the displayed picture by a small amount (between 5-10% edge crop) to ensure that at no time would the hidden areas be visible.

Although modern digital electronics have eliminated the issue of shifting image position, unfortunately, some TV manufacturers have included overscan on their flat screen TVs. Why? Because for many years it was given that the edge of the visible image would rarely be seen, so broadcasters would sometimes overlay “hidden” data to the very edge of the image (e.g. some types of closed captions). Also, legacy analog recordings might still contain unwanted noise around the edge. To avoid consumer complaints, overscan is quite often enabled by default. For some flat screen TVs, it is not possible to disable it.

Habilitando as áreas seguras

Blender has configurable safe-area markings which can be made visible by selecting the scene camera, then in the camera settings by enabling Safe Areas. Several presets are available. If you are producing work for a television network or indeed any client, they may have their own rules and requirements on safe area dimensions – so consult with them.

Reprodução de cores

When exporting to many of the common video formats, the rendered RGB(A) images go through a conversion process whereby they are translated to the YCbCr color model. Y corresponds to a gray-scale representation of the image, Cb and Cr contain data for the blue and red channels respectively. Green is encoded into the Y and Cb, Cr channels with some clever math.

Importantly, the color components are often stored at a lower resolution to the Y (grayscale) channel. This can cause blurring/smearing which can be a problem with small text and some saturated color combinations – so it is well worth doing test encodes to make sure that text remains legible. As with safe areas, a TV network or client might have their own rules on minimum text size and positioning, so always seek clarification when unsure.

Painel Codificar

Referência

Panel:Properties editor ‣ Render ‣ Encoding
../../_images/render_output_video_encoding-panel.png

O painel Codificação.

Here you choose which video container, codec, and compression settings you want to use. With all of these compression choices, there is a trade-off between file size, compatibility across platforms, and playback quality.

Dica

When you view the System Console, you can see some of the output of the encoding process. You will see even more output if you execute Blender as blender -d.

Predefinições
You can use the presets, which choose optimum settings for you for that type of output.
Contêiner
Video container or file type. For a list of all available options, see video formats.
Dividir automaticamente a saída
If your video is huge and exceeds 2GiB, enable Autosplit Output. This will automatically split the output into multiple files after the first file is 2Gig.
Codificador
Chooses the method of compression and encoding. For a list of all available options see video formats.

Nota

Padrões

Alguns contêineres e codificadores não são compatíveis entre si, portanto, se você está sendo informado sobre erros, verifique se o seu contêiner e codificador são compatíveis. Da mesma maneira que alguns contêineres e codificadores são algumas vezes incompatíveis entre si, alguns codificadores não funcionam com dimensões arbitrárias. Portanto, tente permanecer nas dimensões mais comuns ou pesquise sobre as limitações do codificador que vocẽ está tentando utilizar.

Qualidade de saída
Estas são as taxas predefinidas.
Velocidade de codificação
As predefinições permitem a alteração entre uma codificação rápida (com um maior tamanho de arquivo) e mais compressão (menor tamanho de arquivo).
Keyframe Interval
The number of pictures per Group of Pictures. Set to 0 for «intra_only», which disables inter-frame video. A higher number generally leads to a smaller file but needs a higher-powered device to replay it.
Máximo de quadros-b

Habilita o uso de quadros-b.

Intervalo
O número máximo de quadros-b entre os quadros não b.

Taxa

Taxa de bits
Sets the average bit rate (quality), which is the count of binary digits per frame. See also: FFmpeg -b:v.
Taxa
Video files can use what is called variable bit rate (VBR). This is used to give some segments of the video less compressing to frames that need more data and less to frames with less data. This can be controlled by the Minimum and Maximum values.
Contingenciador (buffer)
The decoder bitstream buffer size.

Multiplexador

A Multiplexação é o processo de combinar fluxos separados de áudio e vídeo em um único arquivo, similar ao empacotamento de um arquivo de vídeo e um arquivo de áudio em formato mp3 em um único arquivo em formato zip.

Taxa
A taxa de bits máxima do fluxo multiplexado.
Tamanho do pacote
Reduz a fragmentação de dados ou sobrecarga do multiplexador dependendo da fonte.

Áudio

Codificador de áudio
O formato de áudio a ser usado. Para uma lista de todas as opções disponíveis, veja a página sobre formatos de vídeo.
Taxa de bits
For each codec, you can control the bit rate (quality) of the sound in the movie. Higher bit rates are bigger files that stream worse but sound better. Use powers of 2 for compatibility.
Volume
Define o volume de saída do áudio.

Dicas

Dica

A escolha do formato de vídeo depende do que você planeja fazer.

It’s not recommended to render directly to a video format in the first instance. If a problem occurs while rendering, the file might become unplayable and you will have to re-render all frames from the beginning. If you first render out a set of static images such as the default PNG format or the higher-quality OpenEXR (which can retain HDR pixel data), you can combine them as an Image Strip in the Video Sequence Editor (VSE). This way, you can easily:

  • Reiniciar a renderização a partir do lugar (o quadro) onde quaisquer problemas tenham ocorrido.
  • Tente diferentes opções de codificação de vídeo em relação aos segundos ao invés de minutos ou horas, devido ao fato de ser comumente muito mais rápido codificar um vídeo do que renderizar as cenas em 3D.
  • Enjoy the rest of the features of the VSE, such as adding Image Strips from previous renders, audio, video clips, etc.

Dica

You shouldn’t post-process a lossy-compressed file as the compression artifacts may become visible. Lossy compression should be reserved as a final “delivery format”.

If you are planning on doing significant post-processing and color correction, it is best to output a frameset rendered in OpenEXR format. If you plan to do only minimal changes after rendering and would prefer a single file, choose lossless H.264 for high quality, or regular H.264 for lower quality.