improve faq

issues.md

@@ -1,6 +1,6 @@
 # FAQ
 
-- **Can LosslessCut crop, resize, stretch, mirror/flip, overlay text/images, watermark, blur, redact, re-encode, create GIF, slideshow, burn subtitles, color grading, fade/transition between video clips, fade/combine/mix/merge audio tracks or change audio volume?**
+- **Can LosslessCut crop, resize, stretch, mirror/flip, overlay text/images, watermark, blur, redact, reduce quality/re-encode, create GIF, slideshow, burn subtitles, color grading, fade/transition between video clips, fade/combine/mix/merge audio tracks or change audio volume?**
   - No, these are all lossy operations (meaning you *have* to re-encode the file), but in the future I may start to implement such features. [See this issue for more information](https://github.com/mifi/lossless-cut/issues/372). See also [#643](https://github.com/mifi/lossless-cut/issues/643).
 - Can LosslessCut be batched/automated using a CLI or API or do external post-processing?
   - While it was never designed for advanced batching/automation, it does have a [basic CLI and a HTTP API](./cli.md). More info: [#980](https://github.com/mifi/lossless-cut/issues/980) [#868](https://github.com/mifi/lossless-cut/issues/868).
@@ -29,10 +29,15 @@ They have exactly the same in-app features, except for a few platform limitation
 
 # Primer: Video & audio formats vs. codecs
 
-Here's a little primer about video and audio formats for those not familiar. A common mistake when dealing with audio and video files, is to confuse *formats*, *codecs*, and *file names*. In short: A file's media format is a *container* that holds one or more *codecs* (audio/video/subtitle) inside of it. For example `.mov` is a *container format*, and `H265`/`HEVC` is a *codec*. Some formats support some particular codecs inside of them, while others support other codecs. The most common formats are arguably Matroska (often `.mkv`) and MP4/MOV (often `.mp4`/`.mov`) as well as their derivatives. Example: If you have a file named `My video.mp4`, this file most likely (but not necessarily) has the *format* `MP4`. Note that the extension of a file (in this case `.mp4`) doesn't really mean anything, and the file could in reality for example have the `MOV` format, or the extension could be `.txt`. Inside `My video.mp4` there are multiple tracks/streams, each with their own *codec*. In this example, let's say that it contains one `H264` track and one `AAC` track. In LosslessCut you can view and add/delete/modify these tracks.
+Here's a little primer about video and audio formats for those not familiar. A common mistake when dealing with audio and video files, is to confuse *formats*, *codecs*, and *file names*. In short: A file's media format is a *container* that holds one or more *codecs* (audio/video/subtitle) inside of it. For example `.mov` is a *container format*, and `H265`/`HEVC` is a *codec*. Some formats support only a few codecs inside of them, while others support more codecs. The most common formats are MP4/MOV (often `.mp4`,`.mov`,`.m4a`) and Matroska (often `.mkv`,`.mka`). Example: If you have a file named `My video.mp4`, this file most likely (but not necessarily) has the *format* `MP4`. Note that the extension of a file (in this case `.mp4`) doesn't really mean anything, and the file could in reality for example have the `MOV` format, or the extension could be `.txt`. Inside `My video.mp4` there are multiple tracks/streams, each with their own *codec*. In this example, let's say that it contains one `H264` track and one `AAC` track. In LosslessCut you can view and add/delete/modify these tracks.
 
 **Remuxing**: If you change the output format in LosslessCut and export a file, you are *remuxing* the tracks/codecs into a different container format. When you do this, the operation is in theory lossless, meaning you will not lose any codec data and the different tracks will remain exactly the same, even though the format is now different (but some format metadata might get lost due to incompatibilities between container formats). There are limitations: Some popular codecs like VP8 or VP9 are not supported in popular formats like MP4, and some popular formats like Matroska (`.mkv`) are not natively supported in popular video players like iPhone or QuickTime.
 
+If you want to reduce the size of a file using LosslessCut you have to "get rid of" something, either:
+- Reduce the duration of the file (cut off start/end)
+- Remove one or more tracks/streams (e.g. remove an audio track that you don't need)
+Other than that you it's not possible convert a file losslessly to reduce its size, unless you re-encode and lose quality. For that, I recommend using a different tool like e.g. [HandBrake](https://handbrake.fr/).
+
 Here is a great introduction to audio/video: [howvideo.works](https://howvideo.works/).
 
 # Common / known issues & troubleshooting
@@ -91,7 +96,7 @@ Smart cut is experimental, so don't expect too much. But if you're having proble
 
 ## MP4/MOV issues
 
-Some MP4 files FFmpeg is not able to export as MP4 and MOV needs to be selected instead. Unfortunately I don't know any way to fix this. Sometimes certain players are not able to play back certain exported `.mov` files ([Adobe Premiere](https://github.com/mifi/lossless-cut/issues/1075#issuecomment-2327459890) 👀). You can try to rename the exported MOV file extension to `.mp4` and see if it helps. Or vice versa, rename an exported MP4 file to `.mov`.
+MP4 and MOV are technically almost the same format. Sometimes files have the extension `.mp4` but are in reality the MOV format (and vice versa). MOV tends to be more lenient in which codecs it supports. FFmpeg has problems exporting some MP4 files as MP4, so MOV needs to be selected instead. Unfortunately I don't know any way to fix this. Sometimes certain players are not able to play back certain exported `.mov` files ([Adobe Premiere](https://github.com/mifi/lossless-cut/issues/1075#issuecomment-2327459890) 👀). You can try to rename the exported MOV file extension to `.mp4` and see if it helps. Or vice versa, rename an exported MP4 file to `.mov`.
 
 ## Output file name is missing characters (Chinese, accents etc)