Minimoto wrote:First of all, don't download your footage from the net and buy the DVDs?
NeoQuixotic wrote:Another issue with YouTube and other sites is they change the way they encode things randomly. I used to be able to encode H.264 MP4s to the specs that YouTube used and it wouldn't even be re-encoded, but they now re-encode everything. They also seem to now encode everything to 29.97 or even 30 fps. So your 23.976, 24, 25, etc will no longer be encoded in its native frame rate. Now I haven't really seen the video to play visually different, but it's still annoying. Other times it keeps the native frame rate, makes it some random non-standard rate, or even a variable frame rate. Vimeo also converts everything to 24 fps last time I heard. Google uses or at least used to use ffmpeg, x264, and other open source tools for their encoding, so quality issues might change when they update their tools too. I can't complain too much being that YouTube is free and offers 1080p now.
Here is a little breakdown of the bitrates YouTube uses (H.264/AAC):
1080p • Video ~3800 Kbps | Audio ~125 Kbps | MP4 container
720p • Video ~2200 Kbps | Audio ~125 Kbps | MP4 container
480p HQ • Video ~850 Kbps | Audio ~125 Kbps | FLV container
480p LQ • Video ~450 Kbps | Audio ~125 Kbps | FLV container
270p • Video ~375 Kbps | Audio ~125 Kbps | MP4 container
These bitrates are decent, but with high motion or very detailed video it isn't so pretty. All the MP4 container encodes report as a variable bitrate, so assuming YouTube's encoding does any sort of analysis it should help a bit. I've also seen the bitrates vary depending on length and sometimes just randomly. Now we have no control over how the video gets re-encoded on YouTube or elsewhere, but we can try to upload the highest quality file possible. The ideal situation would be to upload a lossless version. However, the issue is the file size is generally way too big to upload, especially when 720p or higher. I also wouldn't expect sites to be able to convert a lossless format. YouTube does work with huffyuv, but not lagarith. I also tried lossless x264 and it encoded, but was screwed up. My solution was to use a constant quantizer or constant quality mode in x264. I found using x264 with CRF 18 (modifed from MeGUI "Unrestricted 1Pass MaxSpeed" profile) to give a decent file size and excellent quality; also it encodes very fast.
Quantizer/Bitrate: This setting is basically a trade-off between visual quality and filesize. If you are using bitrate mode, then you simply set the bitrate that you want to encode your video at. Higher bitrates increase the size of your output file, and you can see the estimated filesize as you modify the bitrate value. If you are using constant quality mode, then this is where you select the quantizer to use. Valid values are from 0-51, with lower values giving better quality, but larger filesizes. A quantizer of 18 is generally considered the lowest that you should select, as it's unlikely that you will see much visual improvement by going any lower. For those of you familiar with Xvid, a quantizer of 18 here is equivalent to Xvid's quantizer 2. The default quantizer value is 22, which gives a rather decent tradeoff between quality and size.
Zarxrax wrote:Youtube encodes 2 versions. A low quality version and a high quality version. Are you sure you weren't just looking at the low quality one?
Users browsing this forum: No registered users and 0 guests