Subtitling ProRes Videos – Are Large Files Necessary?

When embarking on a subtitling project for the first time, the first client concerns we encounter are often around working with large files. These concerns can be centred around time constraints in uploading and downloading large files, or concerns with regards to the input and output quality of videos. In terms of subtitling with high spec videos, including subtitling ProRes videos, there are some fundamental things to consider. 

Does video quality matter for subtitling and closed captioning?

The importance of video quality on subtitling often very much depends on the subtitle format required. Standard SRT files can be created from very low res files, however, subtitles for digital cinema packages (DCP) or broadcast often need to be worked on in a way that the resolutions and spec match the source video. In most cases, our advice when it comes to closed captioning, is if there are time constraints, aim to work with smaller videos in order to increase turnaround. Working with subtitling services often requires downloading, uploading and indexing video multiple times during the work receipt, allocation and QC processes. The larger the video, the more time this takes. Subtitling ProRes videos is fine if you don’t need to take time into account. 

What video specs do Capital Captions recommend?

Capital Captions’ recommendation is nearly always to aim to work with smaller videos for ease of use. The most important element to consider when working with compressed video is to ensure that there is no change in frame rate, as this can have a significant impact on timings. When it comes to creating subtitles, timing is absolutely key. If a video is subtitled in the wrong frame rate, the subtitles will drift out of sync as you watch back your target video. Broadcast, VoD and cinema subtitles should be accurate to within one frame, and ideally, subtitles should not straddle across shot changes. Frame rate differences can have a huge impact on this.

Just remember, in terms of other elements if you do decide to compress your video as long as the resolution either matches the final cut, or your captioning company is made aware of the target resolution, the spec can be changed during the subtitling process. As long as the timings and frame rate remain stable, the transcription and subtitling process should not be affected by working with smaller videos.

The next issue in terms of video size can be price. Working with ProRes and videos from the grade is time consuming and has a high demand on IT packages. Often subtitling companies will actually need to convert these videos and compress them in order to make them workable. Adding this extra process can cost extra money, so working with large files can have a negative impact on your budget.

Is BITC important when subtitling videos?

Often, grade video comes with a test screen and BITC. This is usually not necessary for subtitling. If your video distributor has requested that your video start from a specific code outside of zero, then this can be stipulated and subtitles offset accordingly on completion of work. Burned in time codes can be useful for subtitling companies to confirm frame rates and timing accuracy against captioning software. Outside of this slight benefit, there is really no requirement for burned in timecodes when subtitling. 

Large Videos for Subtitle Burning

One time when video quality does matter is if you would like to display your subtitles permanently on your video. In this case, the quality of your output video can only ever match that of the input video, therefore it’s always advisable to work with the highest quality where possible. However, even in this case, it usually isn’t necessary to work from the grade but rather to render a compressed video in high resolution. If you are interested in learning more about subtitle burning why not take a look at our Subtitle burning and formatting specification.

What are advantages / disadvantages of working with grade video?

To summarise, whilst many production companies may like the idea of working with grade video to ensure high quality, the impracticalities of working with large video often outweigh any benefits. As long as you work with a high quality video, there’s no need to use ProRes video for subtitling purposes. Doing so often involves higher costs, potential upload and download issues and accepting slower turnaround times for your projects. 

So there you have it, the advantages and disadvantages of subtitling ProRes videos and the effects it can have. In the end the decision truly comes down to personal preference. If you would like more information about our subtitling services, closed captioning services, translation or voiceover services contact us today or hot the quote button below to get started.