August TV recorder bitrate

[techmot]

I have a small TV PVR recorder called an August TV recorder which receives HD channels and allows you to record (onto a pendrive) terrestrial TV programmes. The quality of the outputted file is amazing I must say, don't think there is any difference in quality, but it records to an MTS extension. What I find odd about it when I record some programmes from the same channels (and in the same resolution) is that the audio bitrate seems to change; some recordings are at 192kbps but others are at only 64kbps. Why aren't the audio bitrates the same?. Is this down to the broadcast output?. Also, if I want to encode these files to MP4 using Handbrake, should I set the bitrate at the original bitrate of the file (ie 64) or at a higher bitrate?.

The other odd thing about this TV recorder is that, after around 40 mins of recording, when I connect the pendrive that the programme was recorded on into my laptop, it has recorded two separate files, one a readable MTS file and the other an unreadable MTS1 file. Playing the recording on the machine the file is all complete. I can encode the other file in Handbrake but that means losing quality (unless I use the lossless option which creates a file of about 2GB for what was originally a 170MB file), editing programmes won't read the file.

[jagabo]

Why aren't the audio bitrates the same?. Is this down to the broadcast output?.

Recorders like that simply save the broadcast stream. Whatever is broadcast is what's in the MTS file.

Also, if I want to encode these files to MP4 using Handbrake, should I set the bitrate at the original bitrate of the file (ie 64) or at a higher bitrate?.

Reencoding the audio to a higher bitrate will not improve the quality. The damage has already been done. Why are you converting to MP4? Are you planning to encode at a lower bitrate to reduce the file size? Audio is usually a pretty small part of the overall file -- just keep the original audio. If your converting to MP4 just because you prefer MP4 to MTS (maybe you have a player that doesn't play MTS?), just remux the video and audio. There will be no loss of quality.

The other odd thing about this TV recorder is that, after around 40 mins of recording, when I connect the pendrive that the programme was recorded on into my laptop, it has recorded two separate files, one a readable MTS file and the other an unreadable MTS1 file. Playing the recording on the machine the file is all complete. I can encode the other file in Handbrake but that means losing quality (unless I use the lossless option which creates a file of about 2GB for what was originally a 170MB file), editing programmes won't read the file.

You might be able to simple concatenate the files. Even better, check the format of your USB drive. If it's FAT32 reformat it to a more modern file system, one that supports files larger than 4 GB. NTFS, exFAT, EXT4, whatever the recording device can deal with.

[techmot]

Why aren't the audio bitrates the same?. Is this down to the broadcast output?.

Recorders like that simply save the broadcast stream. Whatever is broadcast is what's in the MTS file.

Also, if I want to encode these files to MP4 using Handbrake, should I set the bitrate at the original bitrate of the file (ie 64) or at a higher bitrate?.

Reencoding the audio to a higher bitrate will not improve the quality. The damage has already been done. Why are you converting to MP4? Are you planning to encode at a lower bitrate to reduce the file size? Audio is usually a pretty small part of the overall file -- just keep the original audio. If your converting to MP4 just because you prefer MP4 to MTS (maybe you have a player that doesn't play MTS?), just remux the video and audio. There will be no loss of quality.

The other odd thing about this TV recorder is that, after around 40 mins of recording, when I connect the pendrive that the programme was recorded on into my laptop, it has recorded two separate files, one a readable MTS file and the other an unreadable MTS1 file. Playing the recording on the machine the file is all complete. I can encode the other file in Handbrake but that means losing quality (unless I use the lossless option which creates a file of about 2GB for what was originally a 170MB file), editing programmes won't read the file.

You might be able to simple concatenate the files. Even better, check the format of your USB drive. If it's FAT32 reformat it to a more modern file system, one that supports files larger than 4 GB. NTFS, exFAT, EXT4, whatever the recording device can deal with.

I am wanting to import the files so that I can edit the ad breaks out. Lossless cut does a poor job of making precise cuts because of the keyframes, so I have to use editing programmes like Premiere where you need to recode the files. If the different audio bitrates is down to the actual broadcast then that's strange, why would the broadcaster do this?, unless it's something to do the machine. As for remuxing, how do you remux MTS files to MP4? you can't, not in programmes like OBS.

I tried recording the programmes I was recording in two parts where there was ad breaks; I stopped the recording after about 30 mins and then recorded again when the programme started again after another advert. I checked the file on my computer and there was no unreadable file this time only the two separate files as they were recorded. So it seems that this maybe due to the pendrive not being able to record more than 40 mins.

[jagabo]

I am wanting to import the files so that I can edit the ad breaks out. Lossless cut does a poor job of making precise cuts because of the keyframes, so I have to use editing programmes like Premiere where you need to recode the files.

There are also "smart" editors that will re-encode only the cut GOPs. So they are very fast and you don't lose quality for the bulk of the video. VideoRedo and TMPGEnc MPEG Smart Renderer are two.

If the different audio bitrates is down to the actual broadcast then that's strange, why would the broadcaster do this?

Probably because that's what they are given to broadcast.

As for remuxing, how do you remux MTS files to MP4?

AviDemux is one tool (GUI). ffmpeg is another. With ffmpeg the basic command is:

ffmpeg -i input.mts -c copy output.mpg

But you may need something a little different depending on the codecs used in the source. Or try one of the GUI front ends for ffmpeg.

I tried recording the programmes I was recording in two parts where there was ad breaks; I stopped the recording after about 30 mins and then recorded again when the programme started again after another advert. I checked the file on my computer and there was no unreadable file this time only the two separate files as they were recorded.

Of course. Those are two completely separate recordings.

So it seems that this maybe due to the pendrive not being able to record more than 40 mins.

When the device splits the file automatically you get one recording split into two separate files. The second file isn't a separate recording. To Information in the first may be required to play the second part -- because they are supposed to be a single file. But as I indicated before, you may be able to concatenate the two files to get a single file that will play/edit properly. This can be done with a command line like:

copy /b part1.mts+part2.mts output.mts

or with GUI based tools that do the same thing.

[techmot]

I am wanting to import the files so that I can edit the ad breaks out. Lossless cut does a poor job of making precise cuts because of the keyframes, so I have to use editing programmes like Premiere where you need to recode the files.

There are also "smart" editors that will re-encode only the cut GOPs. So they are very fast and you don't lose quality for the bulk of the video. VideoRedo and TMPGEnc MPEG Smart Renderer are two.

If the different audio bitrates is down to the actual broadcast then that's strange, why would the broadcaster do this?

Probably because that's what they are given to broadcast.

As for remuxing, how do you remux MTS files to MP4?

AviDemux is one tool (GUI). ffmpeg is another. With ffmpeg the basic command is:

ffmpeg -i input.mts -c copy output.mpg

But you may need something a little different depending on the codecs used in the source. Or try one of the GUI front ends for ffmpeg.

I tried recording the programmes I was recording in two parts where there was ad breaks; I stopped the recording after about 30 mins and then recorded again when the programme started again after another advert. I checked the file on my computer and there was no unreadable file this time only the two separate files as they were recorded.

Of course. Those are two completely separate recordings.

So it seems that this maybe due to the pendrive not being able to record more than 40 mins.

When the device splits the file automatically you get one recording split into two separate files. The second file isn't a separate recording. To Information in the first may be required to play the second part -- because they are supposed to be a single file. But as I indicated before, you may be able to concatenate the two files to get a single file that will play/edit properly. This can be done with a command line like:

copy /b part1.mts+part2.mts output.mts

or with GUI based tools that do the same thing.

Thanks for that. I gave Avidemux a try and I was very surprised to see it is quite good at cutting, much better than Lossless cut where it allowed me to make precise cuts that a video editing programme would do, and importing the MTS files from the TV recorder I used to record a TV programme on from a pendrive, it was very smooth scrolling through the timeline, no real frame stuttering or lagging; though I did try another file in MP4 which seemed to make the audio out of sync, but could've been the codec. I don't know why I have never used Avidemux before. I cut the ads out and then selected the copy mode and just saved and it was very quick, so I'm guessing it has just done a straight forward remux to MKV.

[jagabo]

Yes, with video and audio in "copy" mode it is lossless and is restricted to keyframe cuts, just like all the other lossless editors.

[techmot]

Yes, with video and audio in "copy" mode it is lossless and is restricted to keyframe cuts, just like all the other lossless editors.

Well if it's restricted by keyframe cuts in that mode, then it does a far better job than what Lossless Cut does. Lossless doesn't seem to cut where there are keyframes, sometimes it does and sometimes it doesn't, I know that sounds weird but it does do this. And also Lossless Cut is very sluggish, but AviDemux isn't. Maybe I need to update it. I was quite impressed to see it was able to trim exactly where I wanted, with nothing I wanted to leave in missing not even for a second, maybe it's because it just cut the ad breaks out and these would've been easier for the programme to detect.

[techmot]

Regarding Avidemux again, but does anyone know why it won't allow me to import/add more than one file?. I tried this the other day and I was able to add more than one file, but now when I click one file and then try and add another it just replaces with the new file, it doesn't add the file at the end of the other film or before it on the editing timeline.

[jagabo]

Are you sure you used File -> Append rather than File -> Open?

[techmot]

Are you sure you used File -> Append rather than File -> Open?

Managed to sort it, I just opened up the folder separately and not go to file and open, just dragged the file over and it imported it.