Any video experts? Optimal bitrate question.

[CaliforniaCowboy]

Converting some video files (Movies/shows) down in size to be stored and watched on my cell phone.
phone res is..
1920x1080 367ppi 16/9 aspect ratio

I am looking to make videos look as good on my phone as possible. To get the best picture but do not want to make the video files larger than that, no sense having extra data that can not be displayed.

Some of the movie files are HD 12 or 20 GB movies. Some are 30 min shows at 2 gigs or so, some larger.

I am converting to mpeg4 ( unless you think there is a better format) to 1920x1080 16/9. But am not sure what I should set my bitrate to for the conversion. The original video is pretty dang high. I am not sure however what is the best bitrate for my resolution, would rather go a little higher than lower but do not want to be using a rate way more than can be used and just have wasted storage. But I really have no knowledge about bitrate, most of what I have read tonight has to do with streaming video, I am not streaming, just playing from storage to device.

Also, If I do set my bitrate too high, could that cause playback issues?


Another question, If I have a video files on my pc that are at a res of 1280x718 will it fit my screen better or look better if I convert it to my phones resolution of 1920x1080? if so, should I also bump up the bitrate above what the origional was or would that not make any difference at all?

[MrFancyPants]

My first question is what software are you using to encode your video? I'd highly recommend using Handbrake if you're not already, because it's free and does an excellent job, plus has huge community support.

Now, 12 or 20 GB movie files and 2 GB half hour shows are way too big. To give you a comparison, I encode my own movies from blu ray originals to watch on my tablets for when I go on trips, and my full HD 2 hour long movies come in at under 2 GB. One hour TV shows end up under 1 GB. My tablets are 8 inch and I bet you couldn't tell the difference between the encoded files and the original blu ray. I know I can't and I'm extremely picky about quality. Heck, I can barely tell the difference on a 27" 1080p monitor at home.

If you use Handbrake to encode your videos, you shouldn't be choosing a constant bit rate. You should select the other encoding options and use variable bit rate, let the encoder determine optimal bit rate given the frame and other options you've chosen. If you want a list of my typical Handbrake settings for encoding video for mobile devices, PM me. For example, I always encode mobile video in 720p, because you really won't be able to see the difference between that and 1080p video on a mobile screen, especially a cell phone. You also have to consider other limitations of your mobile device, such as if you're using standard headphones, then you should only encode the audio in a compressed 2.0 channel format like MP3 320 kbps, since passing through uncompressed DTS and other formats creates an unnecessarily large audio stream.

MP4 is a good container choice for mobile video, or any video for that matter, as long as you don't care about having multiple subtitles available. Elitist encoders will go on and on about why you should use MKV, but unless you need or want the extra features available, MP4 will work fine, and it has better device and software compatibility.

One thing to consider, if you want to transcode a video from an already encoded source which is already lossy, you will be compounding the lossy-ness of the video, meaning every transcode will reduce the quality of the file. It's best to encode from the original media if you have it available.

Regarding files already in 1280x720 resolution, definitely do not re-encode it to 1920x1080. Software has to interpolate up in that scenario, which is essentially a best guess method for filling in the extra data and will result in a crappy quality video. Just leave those videos as is, they will look fine on a 1080p display.

Hope that answers your questions.

[CaliforniaCowboy]

Thanks ^

By the way, I did a test video converting 1280X720 to 1920x1080 and just like you mentioned, it did not turn out well.

I am using "any video converter" currently. I might give handbrake a try.

Normally I would just test out a bunch of conversions and see which looks and works best. That is no issue on my own PC, it is fast but currently have it in storage getting ready for a move to a new house and using the family's old walmart pc. So even converting a 45min show takes for ever. Harder to to a bunch of trial test runs on this dinosaur.

[MoondogIndustries]

Try h264 compression instead of MPEG-4. Your compression codec choice plays a far bigger role in perceived video quality and file size than bit-rate.

[bool1tholz]

Agree with H264 commet above. The reason why is that most mobile devices have a hardware decoder available for H264 playback. I think the hardware support for the codec is more important than the bitrate generally.
But it depends on your device what hardware support it has. Your device might support othercodecs as well but you didn't say what hardware you're using.
I also agree using handbrake and letting it use it's default settings is probably the best way to go for most users.

[MrFancyPants]

Originally Posted by MoondogIndustries

Try h264 compression instead of MPEG-4. Your compression codec choice plays a far bigger role in perceived video quality and file size than bit-rate.

Yes h264/x264 is a much higher quality codec than MPEG-4. Using Handbrake you can use the h264 codec and still drop the video and audio stream into a mp4/m4v container, which allows for one subtitle track, or subtitles can be burned in. The h265 codec would be better but it's still in early stages, and I haven't personally tried it out yet, but I plan to encode some blu rays and do some comparison between h264 and h265.