Is it possible to encode and decode jpeg by blocks?
I want to develop some very specific UDP protocol, with following workflow:
It is very simple in design, and very "realtim'ish", in contrast to stubs like HTTP MJPEG streaming technique: it could fully utulize even narrow channel to deliever as much updates as quickly as possible. Drawbacks are that delivery not guranteed, and frame start and end are not determined - with each packet you know just that "some blocks at that coordinates just have been updated"
But I am very new to libjpeg api. How is it possible to encode frame, but then split bitstream, to pack in packet only "integer" amount of DCT-ized and huffman-encoded blocks? (as it stated in article on how JPEG works)
So can reword the task - Given encoded jpeg file; the goal is to split data stream to chunks up to some maximum size in such a way, that each chunk would contain just suffient data to decode it. (No chunk concatenation is allowed)
jpeg huffman-code mjpeg libjpeg
asked Jan 20 at 3:16
xakepp35xakepp35
892617
add a comment |
I want to develop some very specific UDP protocol, with following workflow:
It is very simple in design, and very "realtim'ish", in contrast to stubs like HTTP MJPEG streaming technique: it could fully utulize even narrow channel to deliever as much updates as quickly as possible. Drawbacks are that delivery not guranteed, and frame start and end are not determined - with each packet you know just that "some blocks at that coordinates just have been updated"
But I am very new to libjpeg api. How is it possible to encode frame, but then split bitstream, to pack in packet only "integer" amount of DCT-ized and huffman-encoded blocks? (as it stated in article on how JPEG works)
So can reword the task - Given encoded jpeg file; the goal is to split data stream to chunks up to some maximum size in such a way, that each chunk would contain just suffient data to decode it. (No chunk concatenation is allowed)
jpeg huffman-code mjpeg libjpeg
asked Jan 20 at 3:16
xakepp35xakepp35
892617
What's the intended use? Why can't you just encode portions of the image?
– ivan_pozdeev
Jan 20 at 3:43
Also note that JPEG is only good for photo-type images, so it's not a good choice for e.g. screencasting.
– ivan_pozdeev
Jan 20 at 3:47
1
@ivan_pozdeev I want to encode portions of image. Each portion must be not more that 1400 bytes (encoded size) and contain integer number of encoded blocks, to be able to decode each portion separately on reciever side. How to do that? Its not screencasting, any parts of image CAN BE LOST due to Ethernet packet loss, it is appreciated, along with commonly known compression artifacts. And unfortunately, question lacks information about global fields of usage and jpeg applications, but instead is trying to focus on a narrow very specific task.
– xakepp35
Jan 20 at 3:56
add a comment |
I want to develop some very specific UDP protocol, with following workflow:
It is very simple in design, and very "realtim'ish", in contrast to stubs like HTTP MJPEG streaming technique: it could fully utulize even narrow channel to deliever as much updates as quickly as possible. Drawbacks are that delivery not guranteed, and frame start and end are not determined - with each packet you know just that "some blocks at that coordinates just have been updated"
But I am very new to libjpeg api. How is it possible to encode frame, but then split bitstream, to pack in packet only "integer" amount of DCT-ized and huffman-encoded blocks? (as it stated in article on how JPEG works)
So can reword the task - Given encoded jpeg file; the goal is to split data stream to chunks up to some maximum size in such a way, that each chunk would contain just suffient data to decode it. (No chunk concatenation is allowed)
jpeg huffman-code mjpeg libjpeg
asked Jan 20 at 3:16
xakepp35xakepp35
892617
I want to develop some very specific UDP protocol, with following workflow:
It is very simple in design, and very "realtim'ish", in contrast to stubs like HTTP MJPEG streaming technique: it could fully utulize even narrow channel to deliever as much updates as quickly as possible. Drawbacks are that delivery not guranteed, and frame start and end are not determined - with each packet you know just that "some blocks at that coordinates just have been updated"
But I am very new to libjpeg api. How is it possible to encode frame, but then split bitstream, to pack in packet only "integer" amount of DCT-ized and huffman-encoded blocks? (as it stated in article on how JPEG works)
So can reword the task - Given encoded jpeg file; the goal is to split data stream to chunks up to some maximum size in such a way, that each chunk would contain just suffient data to decode it. (No chunk concatenation is allowed)
jpeg huffman-code mjpeg libjpeg
jpeg huffman-code mjpeg libjpeg
asked Jan 20 at 3:16
xakepp35xakepp35
892617
asked Jan 20 at 3:16
xakepp35xakepp35
892617
edited Jan 20 at 3:28
xakepp35
asked Jan 20 at 3:16
xakepp35xakepp35
892617
asked Jan 20 at 3:16
xakepp35xakepp35
892617
asked Jan 20 at 3:16
xakepp35xakepp35
892617
892617
What's the intended use? Why can't you just encode portions of the image?
– ivan_pozdeev
Jan 20 at 3:43
Also note that JPEG is only good for photo-type images, so it's not a good choice for e.g. screencasting.
– ivan_pozdeev
Jan 20 at 3:47
1
@ivan_pozdeev I want to encode portions of image. Each portion must be not more that 1400 bytes (encoded size) and contain integer number of encoded blocks, to be able to decode each portion separately on reciever side. How to do that? Its not screencasting, any parts of image CAN BE LOST due to Ethernet packet loss, it is appreciated, along with commonly known compression artifacts. And unfortunately, question lacks information about global fields of usage and jpeg applications, but instead is trying to focus on a narrow very specific task.
– xakepp35
Jan 20 at 3:56
add a comment |
What's the intended use? Why can't you just encode portions of the image?
– ivan_pozdeev
Jan 20 at 3:43
Also note that JPEG is only good for photo-type images, so it's not a good choice for e.g. screencasting.
– ivan_pozdeev
Jan 20 at 3:47
1
@ivan_pozdeev I want to encode portions of image. Each portion must be not more that 1400 bytes (encoded size) and contain integer number of encoded blocks, to be able to decode each portion separately on reciever side. How to do that? Its not screencasting, any parts of image CAN BE LOST due to Ethernet packet loss, it is appreciated, along with commonly known compression artifacts. And unfortunately, question lacks information about global fields of usage and jpeg applications, but instead is trying to focus on a narrow very specific task.
– xakepp35
Jan 20 at 3:56
What's the intended use? Why can't you just encode portions of the image?
– ivan_pozdeev
Jan 20 at 3:43
What's the intended use? Why can't you just encode portions of the image?
– ivan_pozdeev
Jan 20 at 3:43
Also note that JPEG is only good for photo-type images, so it's not a good choice for e.g. screencasting.
– ivan_pozdeev
Jan 20 at 3:47
Also note that JPEG is only good for photo-type images, so it's not a good choice for e.g. screencasting.
– ivan_pozdeev
Jan 20 at 3:47
1
1
@ivan_pozdeev I want to encode portions of image. Each portion must be not more that 1400 bytes (encoded size) and contain integer number of encoded blocks, to be able to decode each portion separately on reciever side. How to do that? Its not screencasting, any parts of image CAN BE LOST due to Ethernet packet loss, it is appreciated, along with commonly known compression artifacts. And unfortunately, question lacks information about global fields of usage and jpeg applications, but instead is trying to focus on a narrow very specific task.
– xakepp35
Jan 20 at 3:56
@ivan_pozdeev I want to encode portions of image. Each portion must be not more that 1400 bytes (encoded size) and contain integer number of encoded blocks, to be able to decode each portion separately on reciever side. How to do that? Its not screencasting, any parts of image CAN BE LOST due to Ethernet packet loss, it is appreciated, along with commonly known compression artifacts. And unfortunately, question lacks information about global fields of usage and jpeg applications, but instead is trying to focus on a narrow very specific task.
– xakepp35
Jan 20 at 3:56
add a comment |
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What's the intended use? Why can't you just encode portions of the image?
– ivan_pozdeev
Jan 20 at 3:43
Also note that JPEG is only good for photo-type images, so it's not a good choice for e.g. screencasting.
– ivan_pozdeev
Jan 20 at 3:47
1
@ivan_pozdeev I want to encode portions of image. Each portion must be not more that 1400 bytes (encoded size) and contain integer number of encoded blocks, to be able to decode each portion separately on reciever side. How to do that? Its not screencasting, any parts of image CAN BE LOST due to Ethernet packet loss, it is appreciated, along with commonly known compression artifacts. And unfortunately, question lacks information about global fields of usage and jpeg applications, but instead is trying to focus on a narrow very specific task.
– xakepp35
Jan 20 at 3:56