1. A computer-implemented method comprising:
receiving, by a computer system, a source video having a source video file size;
determining, by the computer system, a bit rate at which to encode the source video;
encoding, by the computer system, the source video at the determined bit rate to produce an encoded video that has a file size less than the source video file size;
determining, by the computer system, a video quality metric for the encoded video;
determining, by the computer system, whether the video quality metric for the encoded video is within an allowable deviation from a target quality metric; and
encoding, by the computer system, the source video at another determined bit rate when the video quality metric for the encoded video is outside the allowable deviation from the target quality metric.
2. The computer-implemented method of claim 1, wherein encoding the source video at the other determined bit rate is performed iteratively until the video quality metric for the encoded video is determined to be within the allowable deviation from the target quality metric.
3. The computer-implemented method of claim 2, wherein the video quality metric for the encoded video is determined to be outside the allowable deviation when the video quality metric is substantially greater than the target quality metric, and wherein the other determined bit rate is selected to be lower than the bit rate at which the source video was encoded in a previous iteration.
4. The computer-implemented method of claim 2, wherein the video quality metric for the encoded video is determined to be outside the allowable deviation when the video quality metric is substantially less than the target quality metric, and wherein the other determined bit rate is selected to be higher than the bit rate at which the source video was encoded in a previous iteration.
5. The computer-implemented method of claim 1, wherein the video quality metric for the encoded video corresponds to at least one of a structural similarity (SSIM) index, a multi-scale structural similarity (MS-SSIM) index, or a peak signal-to-noise ratio (P SNR).
6. The computer-implemented method of claim 1, wherein the target quality metric corresponds to a structural similarity (SSIM) index of 0.975.
7. The computer-implemented method of claim 1, wherein determining the bit rate further comprises selecting the bit rate using, at least in part, a root finding algorithm.
8. The computer-implemented method of claim 7, wherein the root finding algorithm corresponds to at least one of Brent’s method, Newton’s method, a bisection method, a secant method, an interpolation method, or a combination thereof.
9. The computer-implemented method of claim 1, further comprising:
storing the encoded video when the video quality metric for the encoded video is within the allowable deviation from the target quality metric.
10. The computer-implemented method of claim 9, further comprising:
providing access to the encoded video in response to a media request.
11. The computer-implemented method of claim 9, further comprising:
removing the source video subsequent to the encoded video being stored.
12. The computer-implemented method of claim 1, wherein the determined bit rate at which to encode the source video is determined based on historical data.
13. The computer-implemented method of claim 1, further comprising:
receiving an original video prior to receiving the source video;
applying a first-pass encoding process to the original video to produce the source video having the source video file size.
14. The computer-implemented method of claim 13, further comprising:
obtaining data about the original video during the first-pass encoding process.
15. The computer-implemented method of claim 13, wherein applying the first-pass encoding process to the original video includes encoding the original video at a first-pass bit rate to produce the source video having the source video file size.
16. The computer-implemented method of claim 15, wherein the determined bit rate at which to encode the source video is determined based on the first-pass bit rate.
17. The computer-implemented method of claim 1, wherein the computer system is associated with a social networking service.
18. The computer-implemented method of claim 17, wherein the source video is received from an account associated with the social networking service.
19. A system comprising:
at least one processor; and
a memory storing instructions configured to instruct the at least one processor to perform:
receiving a source video having a source video file size;
determining a bit rate at which to encode the source video;
encoding the source video at the determined bit rate to produce an encoded video that has a file size less than the source video file size;
determining a video quality metric for the encoded video;
determining whether the video quality metric for the encoded video is within an allowable deviation from a target quality metric; and
encoding the source video at another determined bit rate when the video quality metric for the encoded video is outside the allowable deviation from the target quality metric.
20. A non-transitory computer storage medium storing computer-executable instructions that, when executed, cause a computer system to perform a computer-implemented method comprising:
receiving a source video having a source video file size;
determining a bit rate at which to encode the source video;
encoding the source video at the determined bit rate to produce an encoded video that has a file size less than the source video file size;
determining a video quality metric for the encoded video;
determining whether the video quality metric for the encoded video is within an allowable deviation from a target quality metric; and
encoding the source video at another determined bit rate when the video quality metric for the encoded video is outside the allowable deviation from the target quality metric.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method of measuring ozone concentration, comprising:
providing an ozone indicator comprising at least (1) a color-change layer comprised of an ozone sensitive ink and (2) an overcoat layer formed on part or the whole of the surface of said color-change layer;
disposing said ozone indicator in an ozone atmosphere; and
calculating a CT value from color difference or size of color-change zone resulting from color change of said color-change layer.
2. The method according to claim 1, wherein the concentration of ozone in the ozone atmosphere is not less than 1000 ppm.
3. The method according to claim 1, wherein said ozone sensitive ink comprises an anthraquinone dye and a cationic surfactant wherein the cationic surfactant is a quaternary ammonium salt.
4. A method of evaluating ozone concentration, comprising:
disposing an ozone indicator in an ozone atmosphere, said ozone indicator comprising at least (i) a color-change layer comprised of an ozone sensitive ink and (ii) an overcoat layer formed on part or the whole of the surface of said color-change layer; and
determining a CT value (ozone concentrationexposure time) from color difference or size of color-change zone resulting from color change of said color-change layer.
5. The method according to claim 4, wherein the ozone atmosphere has an ozone concentration of not less than 1,000 ppm.
6. The method according to claim 5, wherein the ozone atmosphere has an ozone concentration of 3,000 ppm or higher.
7. The method according to claim 4, wherein the ozone atmosphere is an atmosphere where sterilization or disinfection of foods or medical devices is conducted or an atmosphere where disinfection or deodorization of an operation room or clean room is conducted.
8. The method according to claim 4, wherein the CT value is determined based on known data on a relationship of CT to color difference (E) and a relationship of CT to a size of color change zone.
9. The method according to claim 8, wherein the known data is indicated as a graded scale placed along the color-change layer.
10. The method according to claim 8, further comprising calculating an ozone concentration andor exposure time from the CT value.
11. The method according to claim 4, wherein the ozone sensitive ink contains an anthraquinone dye having at least one amino group species selected from the class consisting of primary and secondary amino groups.
12. The method according to claim 11, wherein the ozone sensitive ink further contains a cationic sufactant of the quaternary ammonium salt type.
13. The method according to claim 12, wherein the cationic surfactant of the quaternary ammonium salt type is an alkyltrimethylammonium salt.
14. The method according to claim 11, wherein the ozone sensitive ink further contains an extender.
15. The method according to claim 11, wherein the ozone sensitive ink further contains a resinous binders.
16. The method according to claim 11, wherein the ozone sensitive ink further contains a color component which does not change color in an ozone atmosphere.
17. The method according to claim 4, wherein the overcoat layer comprises a film-forming polymer.
18. The method according to claim 17, wherein film-forming resin is at least one species of water soluble polymer.
19. The method according to claim 4, wherein the overcoat layer does not contain a coloring agent.