Anyone has technical comparison between AVCHD and XDCAM?
- Thread starter lifepo4
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Barry_Green
Moderator
Which XDCAM? XDCAM includes many flavors, including the original SD XDCAM, which recorded MPEG-IMX and DVCAM.
Then there's XDCAM-HD, which is an MPEG-2 codec recording 1440x1080 4:2:0 at either 18, 25, or 35 megabits.
Then there's XDCAM-EX, which is an MPEG-2 codec recording 1440x1080 4:2:0 at 25 megabits, or 1920x1080 4:2:0 at 35 megabits.
Then there's XDCAM MPEG422, which is an MPEG-2 codec recording 1920x1080 4:2:2 at 50 megabits.
Then there's XDCAM-HD, which is an MPEG-2 codec recording 1440x1080 4:2:0 at either 18, 25, or 35 megabits.
Then there's XDCAM-EX, which is an MPEG-2 codec recording 1440x1080 4:2:0 at 25 megabits, or 1920x1080 4:2:0 at 35 megabits.
Then there's XDCAM MPEG422, which is an MPEG-2 codec recording 1920x1080 4:2:2 at 50 megabits.
Barry_Green
Moderator
EX1/EX3 don't use XDCAM HD, they use XDCAM-EX.
Both codecs record 1920x1080 using a long-GoP structure with 8-bit bit depth and 4:2:0 color sampling. Both provide for 1080p, 1080i, and 720p recording.
AVC is an extremely superior codec to MPEG-2. MPEG-2 is about 15 years old, AVC is the current rage and is taking over the world -- it's H.264, as used in AVCHD, AVC-Intra, satellite broadcasts, IPTV broadcasts, web video, everywhere. MPEG-2 is older and less efiicient; on the plus side, MPEG-2 is less processor intensive and therefore easier to edit. It takes about 8x as much processing power to encode AVCHD as it does to encode MPEG-2, and it takes about 3x as much processing power to decode AVCHD as it does to decode MPEG-2.
In general, AVC is acknowledged to be roughly 2x to 2.5x as efficient in encoding as MPEG-2. The higher the bandwidth, the less the edge; the smaller the bandwidth, the more extreme the superiority of AVC over MPEG-2. Sony themselves says that 9 megabits of AVC is visually comparable to 25 megabits of MPEG-2 HDV.
So, at 21mbps for the HMC150 and 35mbps for the EX3, that's about a 1.5x difference in bandwidth. It is my contention that the two codecs will perform comparably.
However, if you're trying to compare the EX1/EX3 against an HMC150, there's far more that comes into play than just the codec! The CMOS vs. CCD issue, the 1920x1080 chipsets against the spatial-offset chipsets, the 1/2" vs. 1/3" differences, etc.
Strictly viewed as a recording format, I would say AVCHD is superior across the board to MPEG-2. We should get a chance to find out when dedicated AVCHD recording devices become available; that will remove the camera head from the equation and allow us to more closely evaluate the performance of the format itself.
Both codecs record 1920x1080 using a long-GoP structure with 8-bit bit depth and 4:2:0 color sampling. Both provide for 1080p, 1080i, and 720p recording.
AVC is an extremely superior codec to MPEG-2. MPEG-2 is about 15 years old, AVC is the current rage and is taking over the world -- it's H.264, as used in AVCHD, AVC-Intra, satellite broadcasts, IPTV broadcasts, web video, everywhere. MPEG-2 is older and less efiicient; on the plus side, MPEG-2 is less processor intensive and therefore easier to edit. It takes about 8x as much processing power to encode AVCHD as it does to encode MPEG-2, and it takes about 3x as much processing power to decode AVCHD as it does to decode MPEG-2.
In general, AVC is acknowledged to be roughly 2x to 2.5x as efficient in encoding as MPEG-2. The higher the bandwidth, the less the edge; the smaller the bandwidth, the more extreme the superiority of AVC over MPEG-2. Sony themselves says that 9 megabits of AVC is visually comparable to 25 megabits of MPEG-2 HDV.
So, at 21mbps for the HMC150 and 35mbps for the EX3, that's about a 1.5x difference in bandwidth. It is my contention that the two codecs will perform comparably.
However, if you're trying to compare the EX1/EX3 against an HMC150, there's far more that comes into play than just the codec! The CMOS vs. CCD issue, the 1920x1080 chipsets against the spatial-offset chipsets, the 1/2" vs. 1/3" differences, etc.
Strictly viewed as a recording format, I would say AVCHD is superior across the board to MPEG-2. We should get a chance to find out when dedicated AVCHD recording devices become available; that will remove the camera head from the equation and allow us to more closely evaluate the performance of the format itself.
Barry_Green
Moderator
Motion handling -- that's not really relevant to the format, that's more about the chipsets. The EX1/EX3 has rolling shutter artifacts, the HMC150 doesn't.
Compression artifacts -- comparable.
Low light performance -- has really nothing to do with the format. The EX1 is going to be about 1/2 stop more sensitive than the HMC150 in progressive mode, and 1 stop more sensitive in 1080i mode. Noise is generally comparable, with a small edge to the EX1 bc of the larger chipset.
Mike Harvey
Veteran
I think I remember reading something about this in one of your posts from NAB... any word about when AVCHD recorders will be out?
Barry_Green
Moderator
Not that I've heard. The press releases just say "later this year."
AVC is an extremely superior codec to MPEG-2. MPEG-2 is about 15 years old, AVC is the current rage and is taking over the world -- it's H.264, as used in AVCHD, AVC-Intra, satellite broadcasts, IPTV broadcasts, web video, everywhere. MPEG-2 is older and less efiicient; on the plus side, MPEG-2 is less processor intensive and therefore easier to edit. It takes about 8x as much processing power to encode AVCHD as it does to encode MPEG-2, and it takes about 3x as much processing power to decode AVCHD as it does to decode MPEG-2.
>>> With ever lower price of storage, I would prefer less efficient one because it is easier on my Mac and more important, much much less time to handle such codec.
In general, AVC is acknowledged to be roughly 2x to 2.5x as efficient in encoding as MPEG-2. The higher the bandwidth, the less the edge; the smaller the bandwidth, the more extreme the superiority of AVC over MPEG-2. Sony themselves says that 9 megabits of AVC is visually comparable to 25 megabits of MPEG-2 HDV.
>>> HDV sometime have obvious macro-blocking due to motion, much less obvious in AVCHD, but I still can see it sometimes.
So, at 21mbps for the HMC150 and 35mbps for the EX3, that's about a 1.5x difference in bandwidth. It is my contention that the two codecs will perform comparably.
>>> What do you think of the JVC GY-HM100U, which uses XDCAM-EX recording onto SDHC? I guess they still use pixel shifting, otherwise it will be my ideal choice.
However, if you're trying to compare the EX1/EX3 against an HMC150, there's far more that comes into play than just the codec! The CMOS vs. CCD issue, the 1920x1080 chipsets against the spatial-offset chipsets, the 1/2" vs. 1/3" differences, etc.
>>> I am fully aware of the rolling shutter issue, hopefully there will be affordable CMOS with global shutter soon.
Strictly viewed as a recording format, I would say AVCHD is superior across the board to MPEG-2. We should get a chance to find out when dedicated AVCHD recording devices become available; that will remove the camera head from the equation and allow us to more closely evaluate the performance of the format itself.[/QUOTE]
>>> Agree, earlier I asked about low light performance, what I mean is the macroblocking when XDCAM (35Mbps) and AVCHD are used, respectively.
Thanks a lot for explanations, when you book will come out?
>>> With ever lower price of storage, I would prefer less efficient one because it is easier on my Mac and more important, much much less time to handle such codec.
In general, AVC is acknowledged to be roughly 2x to 2.5x as efficient in encoding as MPEG-2. The higher the bandwidth, the less the edge; the smaller the bandwidth, the more extreme the superiority of AVC over MPEG-2. Sony themselves says that 9 megabits of AVC is visually comparable to 25 megabits of MPEG-2 HDV.
>>> HDV sometime have obvious macro-blocking due to motion, much less obvious in AVCHD, but I still can see it sometimes.
So, at 21mbps for the HMC150 and 35mbps for the EX3, that's about a 1.5x difference in bandwidth. It is my contention that the two codecs will perform comparably.
>>> What do you think of the JVC GY-HM100U, which uses XDCAM-EX recording onto SDHC? I guess they still use pixel shifting, otherwise it will be my ideal choice.
However, if you're trying to compare the EX1/EX3 against an HMC150, there's far more that comes into play than just the codec! The CMOS vs. CCD issue, the 1920x1080 chipsets against the spatial-offset chipsets, the 1/2" vs. 1/3" differences, etc.
>>> I am fully aware of the rolling shutter issue, hopefully there will be affordable CMOS with global shutter soon.
Strictly viewed as a recording format, I would say AVCHD is superior across the board to MPEG-2. We should get a chance to find out when dedicated AVCHD recording devices become available; that will remove the camera head from the equation and allow us to more closely evaluate the performance of the format itself.[/QUOTE]
>>> Agree, earlier I asked about low light performance, what I mean is the macroblocking when XDCAM (35Mbps) and AVCHD are used, respectively.
Thanks a lot for explanations, when you book will come out?
Barry_Green
Moderator
HMC150 book is in the endless proofread/fix/resubmit stage. It might be done today, I have another version to check and finish.
AVCHD uses variable size blocks, from 16x16 down to 4x4, so if it gets overloaded it can "macroblock" very gracefully, certainly much more gracefully than the fixed-size-block MPEG-2 codec does.
AVCHD uses variable size blocks, from 16x16 down to 4x4, so if it gets overloaded it can "macroblock" very gracefully, certainly much more gracefully than the fixed-size-block MPEG-2 codec does.