Hi I am interested in using uncompressed video data from my HMC150. It appears that one can capture this data during shooting. That's great, but it would require more equipment in the field than I am able to take. Is there a way to get at the uncompressed video data after shooting (e.g. during playback)? I assume that all the video data stored on the SDHC card compressed under the AVCHD codec? I know that there are transcoders to other codecs that may be "less compressed" but I would like to try working with the raw data. Any help would be appreciated. Thanks
HMC uncompressed video data
- Thread starter dkarshmer
- Start date
Nope , once it has been stored/converted to AVCHD, much of the data is discarded
You cannot improve upon it. You can re-encode the AVCHD to other formats, but you lose quality, unless it's a lossless format. Even lossless formats retain the same quality as the AVCHD, not better (it's uncompressed from the AVCHD, not the original raw stream or even uncompressed stream). When people transcode to "less compressed" codecs, it's usually for ease of editing purposes, sometimes for grading or FX.
Note "raw" is different than "uncompressed". Raw usually implies sampling from the sensor directly, before any in-camera processing. If you record HDMI out (e.g. with a black magic intensity pro card) , that's uncompressed not raw. Uncompressed is just the stream devoid of AVCHD compression , but with in camera processing applied
You cannot improve upon it. You can re-encode the AVCHD to other formats, but you lose quality, unless it's a lossless format. Even lossless formats retain the same quality as the AVCHD, not better (it's uncompressed from the AVCHD, not the original raw stream or even uncompressed stream). When people transcode to "less compressed" codecs, it's usually for ease of editing purposes, sometimes for grading or FX.
Note "raw" is different than "uncompressed". Raw usually implies sampling from the sensor directly, before any in-camera processing. If you record HDMI out (e.g. with a black magic intensity pro card) , that's uncompressed not raw. Uncompressed is just the stream devoid of AVCHD compression , but with in camera processing applied
Philip Goetz
Well-known member
Convergent Designs sells the NANOFLASH and HDMI to HDSDI converter (Selectable Bit-Rates from 18 to 280 Mbps) but both of those pieces cost more than the camera and you would still need to add CF cards.
PDR and Philip, thanks for the fyi. I think that I need to go back and look at uncompressed and avchd footage to see if there is a substantial difference. My work is just beginning to require larger projections (16x9') and this issue came up as a result. I appreciate your input.
David
David
Not so. Although previously recorded footage was highly compressed using AVCHD when acquired in-camera, you can output from the HDMI (or component) and get an uncompressed signal of that footage which is lossless since no additional compression is peformed at that point of output.
Understand that uncompressed video still has certain technical specifications, of course, such as being interlaced or progressive, 1080i or 720p. 10 bit or 8bit, 4:2:0 or 4:2:2, etc. These things depend on how the footage was acquired and also the tech specs of a given camera.
Given the choice between transcoding footage from a card (already highly compressed in the case of the HMC150's AVCHD scheme), or, compressing an uncompressed signal to something like Matrox's I-Frame, or to a 10bit Matrox or Blackmagic uncompressed CODEC, for example, I'll take the latter.
Just read the concise, clearly explained literature on Blackmagic-design.com re their solutions for uncompressed post via HDMI output.
Understand that uncompressed video still has certain technical specifications, of course, such as being interlaced or progressive, 1080i or 720p. 10 bit or 8bit, 4:2:0 or 4:2:2, etc. These things depend on how the footage was acquired and also the tech specs of a given camera.
Given the choice between transcoding footage from a card (already highly compressed in the case of the HMC150's AVCHD scheme), or, compressing an uncompressed signal to something like Matrox's I-Frame, or to a 10bit Matrox or Blackmagic uncompressed CODEC, for example, I'll take the latter.
Just read the concise, clearly explained literature on Blackmagic-design.com re their solutions for uncompressed post via HDMI output.