Video Website Datasheets #4: Google Video
January 16, 2008
Not surprisingly (given that Google owns YouTube) there is great similarity between Google Video and YouTube flash encoding. What is surprising is that the bitrate on Google Video is even lower than on YouTube and therefore so is the quality.
Google Video
A. Output Quality
File Format: flv (Flash video)
Video Codec: Sorenson H.263 (FLV1)
Video Resolution: Resizes to 320 x 240
Video Bitrate: 283 kbps
Max. GOP: 60 frames
Frame-rate: As source (in this case 25fps)
Always re-encoded: No. See comments below
Audio Format: MPEG-2 Audio layer 3
Audio Channels: mono
Audio Sampling Rate: 22.05 kHz
Audio Resolution: 16 bit
B. Input Flexibility
Input File Formats include: avi, .asf, .mov, .wmv, .mpg, .mpeg, .mp4, .ra, .ram, .mod, .flv
Input Video Codecs include: H.264, H.263, MPEG 1/2/4, motion JPEG
Input Audio Codecs include: AAC, MP3
Max. Video Length: None
Max. File Size: 100Mb as single file or 1Gb using Desktop Uploader
C. Comments
- The technical guidance on Google Video states that flash files cannot be uploaded, but they can. Files uploaded in flv format (FLV1 compliant – using Sorenson H.263 codec) appear not to be re-encoded, presumably subject to some overall maximum bitrate – limit not yet established.
- Google Video has a much shorter max. GOP (Group of Pictures) setting than YouTube. In particular a maximum of 2 seconds (at 30 fps) between fully-rendered keyframes, as opposed to around 8s with YouTube. That should help quality, but the test video produced distinctly lower quality than YouTube. Partly this will be the result of the 12% lower overall video bitrate (283 kbps plays 320 kbps). It may also reflect that much of this restricted bitrate may be getting used up rendering the more frequent keyframes given the lower max. GOP.
Summary of just the key data affecting video quality for all websites analysed can be found here.
For all Video Datasheet posts click here.
[GoogleVideo=http://video.google.co.uk/videoplay?docid=7191744957200400342&hl=en-GB]
