Video
ID                          : 2
Format                      : AVC
Format/Info                 : Advanced Video Codec
Format profile              : High@L4
Format settings             : CABAC / 1 Ref Frames
Format settings, CABAC      : Yes
Format settings, Reference  : 1 frame
Format settings, GOP        : M=1, N=50
Codec ID                    : avc1
Codec ID/Info               : Advanced Video Coding
Duration                    : 48 min 54 s
Source duration             : 48 min 54 s
Bit rate                    : 49.9 Mb/s
Width                       : 1 920 pixels
Height                      : 1 080 pixels
Display aspect ratio        : 16:9
Frame rate mode             : Variable
Frame rate                  : 50.000 FPS
Minimum frame rate          : 43.478 FPS
Maximum frame rate          : 1 000.000 FPS
Color space                 : YUV
Chroma subsampling          : 4:2:0
Bit depth                   : 8 bits
Scan type                   : Progressive
Bits/(Pixel*Frame)          : 0.481
Stream size                 : 17.0 GiB (100%)
Source stream size          : 17.0 GiB (100%)
Encoded date                : 2024-02-01 09:54:13 UTC
Tagged date                 : 2024-02-01 09:54:13 UTC
Color range                 : Full
mdhd_Duration               : 2934532
Codec configuration box     : avcC

It is a variable so I will approach Atomos as when playing the recorded file on the Zato this is out of sync which is ridiculous as it was recorded on the unit originally.

Thank you John

It looks like the Zato has 4 video format options: H264 XQ, LQ, MQ & HQ....I guess L, M & H is Low, medium and High so I wonder what the X is, could it be variable which is what the unit was set to when I made the recording today? I have tried to look up the differences on the Internet but am getting nowhere.

@sjmackinder

Hi

. . . . I wonder what the X  is, could it be variable which is what the unit was set to when I made the recording today? . . . .

The XQ is the highest quality level and may be why the frame rate mode is variable to keep the average bitrate lower.

Try recording short clips at each of the other settings, analyse them and see if any of those are Constant frame rate. I would suspect not, many streaming devices like the Zato are variable framerate.

John EB

@sjmackinder

Hi.

Did you read their pages regarding using Apple Pro Res RAW?

And the link to further pages on the Apple website suggesting the best solution for editing would be Final Cut Pro?

This is not a mistake. ProRes RAW is a proprietary wrapper intended to be used within the Apple family of products and very anti Microsoft friendly. Combine that with the use of a very long GOP structure and editing and keeping video to audio in sync becomes a nightmare without the correct software to read it fully and apply an encode at the correct frames to keep the audio in sync.

The various H.264 XQH. 264 HQH.264 and MQH.264 LQ just deals with the amount of compression which may include the variability of the frame rate.

The Apple website offers this warning.

Ray.

@CubeAce

Hi Ray

. . . . Did you read their pages regarding using Apple Pro Res RAW? . . . .

Have you cross posted with this topic?

John EB

@johnebaker

Hi John.

No, I considered it but it seemed to me like product bashing which I try to avoid. As much as I hate the way Apple takes advantage of it's customers by locking them into a system and what seems to me to overcharge for the privilege, I do admire the engineering and coding they produce. It just bugs the heck out of me.

Ray.

I have now made 3 additional recordings using 246 HQ, MQ & LQ and in all cases the frame rate is constant, this is a mediainfo for the 246 HQ:

Video
ID                          : 2
Format                      : AVC
Format/Info                 : Advanced Video Codec
Format profile              : High@L4
Format settings             : CABAC / 1 Ref Frames
Format settings, CABAC      : Yes
Format settings, Reference  : 1 frame
Format settings, GOP        : M=1, N=50
Codec ID                    : avc1
Codec ID/Info               : Advanced Video Coding
Duration                    : 7 s 160 ms
Source duration             : 7 s 141 ms
Source_Duration_LastFrame   : -19 ms
Bit rate                    : 49.9 Mb/s
Width                       : 1 920 pixels
Height                      : 1 080 pixels
Display aspect ratio        : 16:9
Frame rate mode             : Constant
Frame rate                  : 50.000 FPS
Color space                 : YUV
Chroma subsampling          : 4:2:0
Bit depth                   : 8 bits
Scan type                   : Progressive
Bits/(Pixel*Frame)          : 0.481
Stream size                 : 42.6 MiB (100%)
Source stream size          : 42.6 MiB (100%)
Encoded date                : 2024-02-02 06:49:44 UTC
Tagged date                 : 2024-02-02 06:49:44 UTC
Color range                 : Full
mdhd_Duration               : 7160
Codec configuration box     : avcC

This is VERY fortunate for me as the Atomos Zato Connect only cost £210 new and is a 5" HD high brightness monitor with up to 1080p60 recording to SD card. I have inserted all 3 clips into ProX14 and the sync is perfect. Thank you all for your inputs, as always extremely useful, Simon

@sjmackinder

Hi Simon

Thanks for the feedback, useful information to know 👍

John EB

@sjmackinder

👍.

I wondered why I could not find more complaints about this on line. It's just the space saving wrapper that is causing problems then. It's a pity there is no information on the website about this.

Ray.

@sjmackinder, @CubeAce

Hi Simon, Ray

Simon - given the tests you did above recording at the different quality settings are all Constant frame rate, was the first video file the backup recording of a streamed session ?

. . . . It's a pity there is no information on the website about this. . . .

There is some info in the manual for the Zato Connect, with respect to backup recording while streaming, it records the backup at the same bit rate used by the RTMP streaming output. the Zato shows this on the display as H.264 ST.

In order to maintain the best bitrate the frame rate mode is often 'variable' to maintain a higher level of 'perceived quality' and avoid dropouts.

John EB

The event was for a Funeral and it was live streamed via Zoom using my Roland V02HD MkII, the Zato was only used for recording the Service & as a video output monitor. As the client did not want a copy, the outcome is unimportant thankfully.

@sjmackinder

Hi

Thanks for the further info, that confirmed my suspicions why the video was variable frame rate and not constant as you got with testing the different recording quality's.

John EB

When I checked after finding the issue I noticed the format was set to 254 XQ which is the ONLY variable frame rate option, typical. I had not up that point even realised how to alter the format options as there was no manual with the product, as is usual these days. In fact when it arrived I noticed around a 1/2 sec latency with HDMi input to screen. At this point I ran an update and it made all the difference. It seems these days, as equipment purchasers, we are now actively required to effectively constantly bring on-line manufacturers design changes, we are almost now R&D Q&A engineers. Each time I log into Zoom there is a new update, mostly to resolve issues as they appear with client reports.