How do AVCHD video cameras record to internal memory

[jparnold]

I will be purchasing a Panasonic video camera in 2 months and have been able to find answers to all questions I could think of (by Google search) EXCEPT the following questions -
How do such cameras record FILES to their internal memory.
Do they record SEPARATE files every time you start/stop recording
OR do they simply concatenate to the end of the last file?

Given that the camera can record to internal memory or external SD card, is it better to record to internal memory and then (later on) COPY/MOVE from the internal memory to the SD card or doesn't it matter as long as the SD card is fast enough to allow recording directly.

Lastly are SD memory cards as safe (as far as NOT becoming corrupted) as say an external USB hard drive (for archiving while away from home).

Thanks

[Terfyn]

I have the HC-V700 (i.e. no internal memory (700M for internal memory)
Each shot is a separate file, even if you only pause between shots and leave the camera ON. The files are labelled 00000.mts, 00001.mts etc. So it is equivalent to the DV and FireWire capture process where you define each shot by the start on the timecode. (i.e. Its all done for you in the camera)
Both the video and the still photos are recorded on the card. The stills have a .jpeg suffix.

The camera also packs in a lot of extra housekeeping files on the card. You will find a list in the Instruction Manual. Panasonic provide a bit of software called HDWriter which is a downloader and sort of editor. I use this to download the video and stills files. (Simply because it sorts out the important stuff from the rest - you can, of course, drag the relevant files across to your PC) This leaves me with a folder on my PC and I use "Import from Digital Media" to load into the Library. There are more direct routes but I feel in control using this method.

I cannot comment on the integrity of SDHC cards. (i have two 32Gb SDHC cards) but when I have downloaded to the PC I re-format the card in the camera. I do not use USB to transfer, preferring to just pop the SD card in the PC reader. The one benefit of SD cards is their ease of storage and portability compared to a hard drive. Class 4 cards are perfectly adequate.

Just one question. Why go for the internal memory? I see no benefit to it when the SD card does it for you. I would get confused as to what is in the memory and what is on the SD card. Just a thought.

[jparnold]

Thanks for your reply and information.

The camera comes standard with 32GB of internal memory and that is why I would use it and also the reason for the question on is it better to use the internal memory or the SD card?

I will be using the camera on a tour of a few weeks and hope that the internal memory (32GB) and a 64GB SDHC will be enough for the trip (total 6 hours approx recording at 1080p). I will also have a tablet PC and so I guess I could always copy the files onto a second SDHC card as a backup every few days. I have only used tapes in the past which are unlikely to give problems (apart from exposure to strong magnetic fields) but am concerned that an SD card could become corrupted during use.

I thought that the files may be recorded each time you press the pause (recording) button. That will make it easier for me as I use "split by scene" when capturing from my tapes in the past.

Thanks again

John

[Terfyn]

Have you had a problem with SD cards?
I use SD cards for a number of purposes, video, audio Zoom H2, in car etc. and AS YET have not had a failure.
BUT there is always the first time.

Re the internal memory. If its there - use it. I suppose it gives a buffer to check on the video before downloading. I don't think you can use both memory and SD card at the same time. Its either - or.
I suppose that with every mass produced media recording systems there will be failures, SD cards, USB sticks, CF cards or hard drives. My only major failure to date was the hard drive on my PC. It was a REAL pain. I now have a backup drive. I am more wary of mechanical storage compared to solid state. I never go to the top of the solid state range, So two 32Gb cards as compared to one 64Gb card.

[jparnold]

No I DON'T have a problem with SD cards HOWEVER my sister once lost photos on a memory card which became corrupted ALSO I know there is at least one program available to try and extract data from corrupted memory cards. Yes I too once had a HD failure but had never had a memory card give problems. I just wanted others opinions.
I would HATE to loose video taken during overseas trips and so wondered would backup to a usb external hard drive be safer.

No I never tried to assume recording to internal memory and SD card simultaneously. I wondered should I record direct to internal memory and then COPY the files from internal memory to SD (and then format the internal memory) rather than directly to SD.

[Terfyn]

As i don't have the internal memory, I cannot comment. There is nothing I could find in the Instruction Manual to advise either way. BUT I certainly think backup is advisable on an important holiday.
Certainly SD Cards are a lighter option for backup than a HD.

May I ask what camera are you looking at? The 920 for example?

[jparnold]

Exactly (the 920). It looks really awesome for a compact camera.
My existing camera is a GS400 with 3CCD which has been great especially with colours (colors) but only SD and pathetic in low light.

[lata]

Hi John

I guess I have just beat you to upgrading to HD, not that it was a race.
I purchased a Panasonic SD 900 last week you don’t say which model you are buying. The latest is 920 I believe.

SD900 has no internal memory so records to SD card.
At the moment I have two 8 Gb cards used for other still cameras but are working just fine. I will be purchasing two more of those.
The 8 Gb is sufficient for approx 40 minutes using 50P and
60 minutes using top quality (HA) avchd 25fps. The default settings (HG) gives 80 minutes.
I think I will be using the smaller 8 Gb cards, if one fails I only loose a bit not all of my recordings, besides the price is right.

I am unsure which option to choose at the moment. 50p or 25fps

Each time you press the record button a new file is created.
The 900 saved the files to a BDMV folder structure not dissimilar to the folder used on a Bluray disc.
The actual files are saved to the “Stream” folder.

I connect the camera via USB, the PC sees the camera as a removable drive, I simply Copy and Paste the files to the hard drive. As Terfyn says they are 00001.mts.
I could of course simply remove the SD card and insert directly to a card reader on the laptop.

I did not get any software with the camera so cannot try the HD Writer.

Good luck with the new camera…..

[jparnold]

Hi Trevor
Yes I intend to purchase a Panasonic X920M. Fairly expensive but my old camera GS400 has served me well for 8 years and the new one hopefully just as long.
The 900 is fairly similar except the 920 is supposed to be better in low light and also supercedes the 900.

Nice 'advice' re using smaller SDHC cards.

Not sure which video 'quality' to record at as I'm not sure if I will 'burn' my edited videos to Blu-ray or usb memory stick.
What is the highest quality to record at if you intend to burn to Blu-Ray? I can't remember the 'native' resolution for Blu-ray.

[lata]

Hi John

My own thoughts are to use 25fps as that is the industries compatible frame rate for 1920 x 1080.
50P 1920 x 1080 is not compatible for Bluray discs. 1280 x 720 x 50P is compatible
50P 1920 would be suitable for USB Memory stick playback.

Now I need to purchase a Bluray burner, a few discs and I am all set. Till then I will be using a memory stick.

But I am the same as you on the bottom of the learning curve for HD video.

The poor light recordings, well I did a quick test and was very impressed, so if the 920 is supposed to be better then it will give excellent results.

[jparnold]

I have no idea how much better the 920 is in low light but every review I have read raves about the low light capabilities.
The lens is f1.5 and at it's 'wide angle' is equivalent to a 29mm lens on a 35mm camera so I also won't need a wide angle lens converter.
Also have a look at https://www.youtube.com/watch?v=5gjVWdx10uY. My GS400 could only record such scenes with the 'gain' cranked up to full leaving a very grainy image.

[jparnold]

I have noticed that Sony have release 4K (4 times resolution) panels (tv).
I assume they will be 3840 x 2160 pixels. I would imagine it would be pointless having one with a screen size less than 55 inches.

I have also noticed the following data in Wikipedia for Blu-Ray disks

Many current Blu-ray players and recorders now support 1920×1080 video at the full 60p and 50p progressive format. Also 1920 x 1080 25i

[Ken Berry]

Yes those players can play progressive video but not as Blu-Ray discs. Many players have been able to play progressive video for some time, including the Play Station 3. But in their original format and on USB players connected to them via USB.

[jparnold]

Hi Ken

Thanks for your input.

I am trying to understand as much as possible about HD before I start to start taking video and subsequent editing.

It would seem that the highest resolution is via a usb memory stick plugged into a 'player' attached to the tv (rather than burning Blu-rays). Is that correct? And using AVCHD?

I guess there also is less loss editing and output to AVCHD given that the input is the same format and therefore no re-rendering required?

Do you know if there is a codec available for playing AVCHD (.m2t) files?

[Ken Berry]

I guess there also is less loss editing and output to AVCHD given that the input is the same format and therefore no re-rendering required?

Essentially, yes to both -- though with a couple of glosses. First, many new model HDTVs these days can play the AVCHD directly from a USB drive plugged directly into the TV, with no player thus required. And as for the quality/AVCHD aspect, don't forget that there is 4K video waiting in the wings. Some of the major brands have already announced the (imminent?) release of 4K players, though there is not much by way of content for them as yet. And then there is h.265...

Do you know if there is a codec available for playing AVCHD (.m2t) files?

Not sure what you mean by that... Of course there are codecs (h.264), and Video Studio -- and other NLEs etc -- all have them. One problem is, though, that some of the major players (such as Sony and Panasonic), while leaders in the AVCHD field, have had -- in the past at least -- slightly different versions. I'm not sure about their current versions. Sony, for instance, claim that they have developed a version which will give very high quality HD video but using much lower compression rates. My own experiments with Sony's Media Studio Pro 12 indicate this might indeed be the case, quality wise. But I could also be confusing the issue with Sony's work on the new h.265 codec...