Anyone know the Panasonic E50 Audio bitrates?

[bluebridge]

Hi.
Can anyone please tell me (definitively) what the audio bitrates are for the various video 'speed' settings (XP/SP/LP/EP/FR) on a Panasonic DMR E50 DVD recorder?

I bought my Panasonic about 20 months ago, and it has performed flawlessly (so far). In addition to converting old VHS to DVD, recording off-air TV, etc., I also have the audio line-inputs and outputs connected to a Tape in/out socket on my HiFi, so that I can use the E50 as an audio recorder for any signal entering the HiFi amp (e.g. FM radio, LPs, CDs, tapes!). Once on DVD, I can then play back through the Hifi. The reason for my query is that I would like to convert some (now quite old) reel-to-reel tape recordings to digital format, and I am interested in getting the best quality for typically 3 hour duration programmes.

I had thought that the Panasonic's audio recording bitrate was 256 Kbps in AC3 (the E50 doesn't have an LPCM option - despite some past marketing claims) at all speeds. But when I check the Panasonic's bitrate-status viewer, the value seems to be 0.2 Mbps with occasional jumps to 0.4 Mbps for all speeds except EP. EP seems to give 0.1 Mbps with occasional jumps to 0.2 Mbps. And anyway, why, when the bitrate is so low, can I still only get a 2-hour audio recording at SP (4 hrs at LP etc.) on the DVD? I'm sure I've seen a post somewhere that claimed 6 hours of LPCM on a DVD. Can anyone point me in the right direction?

Thanks
bluebridge

[steve2713]

I'm sure there's several other ways of checking it as well, but I've found a handy program for checking this sort of stuff to be 'MediaInfo'.

Just drag and drop a VOB file from one of your discs. With my Pioneer 420, it uses 256kbps with all recordings except FINE, which uses uncompressed audio.

[Synergy]

I had thought that the Panasonic's audio recording bitrate was 256 Kbps in AC3 (the E50 doesn't have an LPCM option - despite some past marketing claims) at all speeds. But when I check the Panasonic's bitrate-status viewer, the value seems to be 0.2 Mbps with occasional jumps to 0.4 Mbps for all speeds except EP. EP seems to give 0.1 Mbps with occasional jumps to 0.2 Mbps. And anyway, why, when the bitrate is so low, can I still only get a 2-hour audio recording at SP (4 hrs at LP etc.) on the DVD?

If I'm not mistaken, the bitrate viewer measures only video signals, not audio. I'm assuming that you recorded blank video signals with the audio and that explained why the video bitrate was so low. Since the audio track is 256 Kbps in AC3 no matter what recording mode you select, you should always use the EP mode, although this is quite a waste of DVD space. A 6-hour audio recording takes only about 691.2MB and that's less than 700MB on a CD-R disc, and less than 1/6 of the DVD space. The AC-3 format is eqivalent to MP3 format and not a high quality audio format.

[ZippyP.]

The AC-3 format is eqivalent to MP3 format and not a high quality audio format.

At high enough bitrates (>192 kbps) they both sound pretty good to me. To each his own.

[bluebridge]

Thanks for all the comments folks.

I'm assuming that you recorded blank video signals with the audio and that explained why the video bitrate was so low. Since the audio track is 256 Kbps in AC3 no matter what recording mode you select, you should always use the EP mode, although this is quite a waste of DVD space. A 6-hour audio recording takes only about 691.2MB and that's less than 700MB on a CD-R disc, and less than 1/6 of the DVD space.

True, I am effectively recording just a blank screen with the audio. But I still don't understand why, with such low bitrates (including the video), and hence such small total data quantities, the recording time is limited by the video 'speed' setting. What causes the data space on the DVD to be wasted? (Quick calc: even with a combined bitrate of say 800 kbps, that's 100 kbytes/s or about 360 Mbytes/hour - so would expect a 4.7 Gbyte DVD to hold around 12 hours worth of data.)

If I owned a recorder that permitted LCPM in XP mode, do I still only get 1 hour of audio on the whole DVD? Did I imagine a post somewhere where someone said they could get 6 hours of PCM audio on a DVD?

[Incidentally, re. the AC3/MP3 quality point - I'm appalled at the way Digital Audio Broadcasting (DAB) has been implemented here in the UK. For example, the leading 'classical music' radio station (BBC Radio3) transmits MP2 (which as you know is not as highly compressed as MP3) at 192 kbps. Radio 4 uses only 128 kbps. And I find this latter unbearable when listened to over a HiFi system - on the Carols from Kings College at Christmas for instance, every transient is 'surrounded' by an audible 'halo of distortion'. The relief when switching back to VHF was palpable.
How can the marketing guys keep a straight face when they spout the mantra that we should all upgrade to DAB??]

bluebridge

[Synergy]

But I still don't understand why, with such low bitrates (including the video), and hence such small total data quantities, the recording time is limited by the video 'speed' setting. What causes the data space on the DVD to be wasted? (Quick calc: even with a combined bitrate of say 800 kbps, that's 100 kbytes/s or about 360 Mbytes/hour - so would expect a 4.7 Gbyte DVD to hold around 12 hours worth of data.)

If I owned a recorder that permitted LCPM in XP mode, do I still only get 1 hour of audio on the whole DVD? Did I imagine a post somewhere where someone said they could get 6 hours of PCM audio on a DVD?

I may have mislead you a bit by mentioning that using a DVD to record audio only tracks as a waste of DVD space. Since the recorder is designed to record both video and audio tracks, it has to assume it could only record up to 6 hours of length on a blank disc for the E50 model, other newer models could record up to 8 Hours. But after 6-hour recording, there is still plenty space left because of blank video, which can still be used for future recording. You can then push the Flex Rec button to find out the max rec time left on the disc and continue recording. Since the max rec time allowed also takes into account of both video and audio signals, this means that you can continue recording another audio session using the flex rec mode until you eventually fill the whole disc space, and it should be close to 12 hours of audio tracks. The thing is that you just cannot record 12 hours of audio track in a single session.

If you own a Panasonic HDD-based model or Pioneer model, then you can eventually fill a DVD disc with 6-hour of LPCM audio track, but you may have to do it in so many (definitely more than 6) seaparate recording sessions. Hope this helps you understand the situation better.

[bluebridge]

But after 6-hour recording, there is still plenty space left because of blank video, which can still be used for future recording. You can then push the Flex Rec button to find out the max rec time left on the disc and continue recording. Since the max rec time allowed also takes into account of both video and audio signals, this means that you can continue recording another audio session using the flex rec mode until you eventually fill the whole disc space, and it should be close to 12 hours of audio tracks. The thing is that you just cannot record 12 hours of audio track in a single session.

OK, thanks - I thought the penny had just dropped for me. You're telling me that though the disc might have 'timed out' because of the record mode setting, there is still space on the disc for more recordings - I just have to hit the record button again.
Well.... sort of yes and no! I picked up two of my previously recorded discs that I thought were 'full' with audio-only material (well OK, audio + blank screen). (By the way, I'm talking DVD-RAM discs here.) One of the discs contained 12, nominally half-hour, drama-serial episodes, recorded at EP, but, because of under-run on the programmes, had only used 5 hours 51 seconds. The Functions/Disc-Info option showed 9 minutes free. The Flexible Rec. option told me the maximum recording time available was 9 minutes. Undaunted, I set the input to AV4 (for which I only have the two RCA audio inputs connected from my HiFi - the component-video and s-video sockets are left open/empty), and pressed the red record button on the standalone box. The system recorded for 9 mins 3 seconds and then dropped out of record. On attempting to start record again, I got a Disc Full message on the box (and Cannot record -disc full on the on-screen dialog). I partially deleted 7 mins of the just-recorded programme; the system told me I had 2 mins recording time left. I tried other ways of recording this 2 mins: FR mode to the max (2 mins) allowed, and pressing record; a timer recording of 30 mins duration set for EP. All timed-out at the 6 hours.
The story was the same with the other disc. That had 3 hours 4 minutes audio only recorded at FR (set to fill the disc at the advertized duration of the programme). [I now realize this was silly - but this recording was made a year last January when I was under the mistaken impression that higher quality video modes would/might use higher audio bitrates.] Again there was 2 mins left unrecorded on this disc (at EP), and again, 2 mins more recording was all I got!

I said 'sort of yes and no' because, on examining the surfaces of these discs, it was clear that the first was about half-full and the second less than a third full (as deduced from the dye colour change). So it looks as though there is plenty of data space left on the disc, but Panasonic's 'time-duration book-keeping' algorithm won't let me record more than 6 hours onto a DVD.

....unless someone knows a workaround!


The post I was thinking of where over 6 hours of LPCM had been recorded to DVD was:
https://www.videohelp.com/forum/viewtopic.php?t=236622

[Synergy]

Well.... sort of yes and no! I picked up two of my previously recorded discs that I thought were 'full' with audio-only material (well OK, audio + blank screen). (By the way, I'm talking DVD-RAM discs here.)

I think what makes such a difference is due the technical differences between VR mode and Video mode recording. Apparently Panasonic's VR mode recording pre-allocates the space for each recording session even if the allocated space is not fully utlized, and it cannot be used for another session. However, Video mode recording is linear and sequential, so each recording session is followed by the previous one. While you only intends to record blank video signals, the recording mode selected, however, would probably determine how long the audio tracks could last.

This also points out the deficiencies of using Panasonic recorders (at least for previous models) as audio-only recorders, since no re-writable media could be used to record Video format. Note that the link you provided did confirm that a DVD-RW disc in Video mode was used to record LPCM audio, also the Pioneer models have more flexible recording settings than the Panasonic models, and therefore could record up to 7 hours of LPCM trak in one session. If you don't mind using a DVD-R disc, you should get much longer audio-only recordings.

[bluebridge]

I think what makes such a difference is due the technical differences between VR mode and Video mode recording.

If you don't mind using a DVD-R disc, you should get much longer audio-only recordings.

Thanks for all your comments and suggestions. However, I don't really believe this is what makes the difference. But... I will sacrifice a DVD-R this weekend, in the interests of science, and test your hypothesis. I'll let you know how I get on.

Apparently Panasonic's VR mode recording pre-allocates the space for each recording session even if the allocated space is not fully utlized, and it cannot be used for another session.

This can't be true, since I can just press the red record button (in any mode) and then manually stop the recording. The program will be stored with its actual duration correctly stored (and available from the Direct Navigator). I can then store a second, and a third, and a.... programme in the same way (and with different video mode settings if desired) and the disk only becomes full once I have reached the equivalent of 6 hours in EP mode or 4 hours in LP mode etc. e.g. a 1 hr prog. in SP + a 1.5 hr prog in LP + a 0.75 hr prog in EP fills the disc.
Also, the second disc I mentioned in my last post was a single linear recording, as was clearly apparent from inspecting the disc's dye as mentioned.
My own gut feeling is that the Panasonic's book-keeping algorithms assume a MAX of 6 hours per disc (at EP), and won't let you store more than this. (The 'properties' record for each programme keeps track of the duration time of each programme and its 'speed'). For example again, the FR mode always knows what the maximum time left on a disc is, for any given speed for your next recording, irrespective of the speed settings for your previous recordings.

However, Video mode recording is linear and sequential, so each recording session is followed by the previous one.

I know - that's what I don't like about it. I actually like the concept of DVD-RAM with its equivalent of a File Allocation Table.
I cut my programming teeth on something called the UCSD p-System. A great system for its time; but it had the drawback of writing files to the disk in linear and sequential format. When you deleted files, you then had 'holes' in the linear, sequential space which might or might not have been big enough for your next file (in other words, the familiar vHS recording tape problem). The p-system file-manager had a command called K(runch - which as you might guess krunched all the files together again! Ah wonderful times, when time spent waithing for the operating system was considered free time! A FAT-type system (even when not called by that name) is a so much cleverer idea. I can't imagine any File-system (except perhaps for backup) on a modern computer operating system settling for linear and sequential.
What is DVD Video mode other than glorified tape on a disk (OK I exaggerate slightly), and all in the name of compatibility!

bluebridge

[Synergy]

My own gut feeling is that the Panasonic's book-keeping algorithms assume a MAX of 6 hours per disc (at EP), and won't let you store more than this. (The 'properties' record for each programme keeps track of the duration time of each programme and its 'speed').

You do have a very valid point of which I didn't consider, and I stand corrected. If this is true, then even Video mode may not allow you to record beyond 6 hours of length. In contrast to Panasonic, the Pioneer models seem to have more recording flexibility in addition to the LPCM audio option.