AVI to MP4 question

[ColMac]

I'm working my way through downloading 36 tapes from between 15 & 19 years ago.

These are all DV tapes of family holidays. I am computer literate (build my own PC's) but I have never done anything serious with video

I'm working in Adobe Spark initially with approx 6 mins of video. Spark tells me it cannot read my AVI files from my Panasonic DV camera. I used the Miro utility recommended by Adobe to re-code as mp4.

But I'm worried about quality. The original AVI files for this segment total 1.47Gb. After conversion through Miro, I now have just 151 Mb of files. I'm assuming that mp4 is a more modern format, but is this actually a reasonable conversion?

In total I'm expecting to have 500Gb of AVI files. While I can easily cope with storage of this amount (even with back-ups), it would obviously be easier, faster cheaper etc if I only had to archive mp4 versions at approx 10% of that size.

My questions therefore is - Is it reasonable to use the MP4 versions with that compression in my Adobe Spark show, and would it be worthwhile converting all files to MP4 for long term storage?

Thanks

[Bernix]

Hi,
MP4 format, is a container. What format is your video codec or audio codec in MP4 container (I prefer mkv, but it couldn't be supported with every device), that is what is true format. And yes, it looks reasonable for x264 video and aac audio. Or you can post Mediainfo of your source avi and result mp4 here.
Don't forget proper deinterlace your video, or encode it as interlaced video. Most people here suggest second option.
The quality is depending only at your satisfaction with result. Everybody has different taste and sharp eye.
I have my 800MB source converted to cca 250 x264 with audio untouched so final is progressive 50 fps crf 18 and PCM at 1,5 Mbit/s So video bitrate is about 8000-10000 kbps
Best way is to keep original Avi as well. And tapes too.

Here is my media info of that 250 MB file
Format : Matroska
Format version : Version 4 / Version 2
File size : 243 MiB
Duration : 3 min 33 s
Overall bit rate : 9 536 kb/s
Writing application : Lavf57.25.100
Writing library : Lavf57.25.100

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4
Format settings : CABAC / 16 Ref Frames
Format settings, CABAC : Yes
Format settings, RefFrames : 16 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 3 min 33 s
Width : 720 pixels
Height : 576 pixels
Display aspect ratio : 5:4
Frame rate mode : Constant
Frame rate : 50.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Writing library : x264 core 146 r2538 121396c
Encoding settings : cabac=1 / ref=16 / deblock=1:0:0 / analyse=0x3:0x133 / me=esa / subme=9 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=32 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=18.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Default : Yes
Forced : No

Audio
ID : 2
Format : PCM
Codec ID : A_PCM/INT/LIT
Duration : 3 min 33 s
Bit rate mode : Constant
Channel(s) : 2 channels
Sampling rate : 48.0 kHz
Bit depth : 16 bits
Language : unknown
Default : Yes
Forced : No



Bernix

[Cornucopia]

As mentioned, AVI and MP4 are just the containers. DV compression is around 5.5:1 compared to uncompressed YUV4:2:0. The much newer & more efficient AVC/H264 (which is likely what's being encoded in the mp4) is anywhere from ~20 or 30:1 up to ~300:1 or more depending on quality, so a figure of say 50:1 (aka 10x the savings of the dv) versus uncompressed is in the ballpark.

But WHY are you using Spark? If you are editing, use an editor. Adobe already has a great one called Premiere. Edit your footage there and save the output(s) as larger intermediate formats (usually lossless at 2.2:1) as recommended by Adobe (whom I've never seen touting miro) in a format/container compatible with Spark, not h264/mp4 which normally should be reserved for your end product.

Then open, rework and compile in Spark, saving an MP4 as your product. This will avoid unnecessary losses in conversion that are occurring in your existing workflow.

The DV files are your originals. It is good practice to always keep your originals (the reason should be obvious), even if you create other newer, more efficient & compatible versions (such as h264/mp4) for everyday use.

Scott

[_Al_]

......oops
wrong reading, yes overall 10:1 compression (including PCM to AAC 192kbps) gives QTGMC deinterlacer while using CRF 18, that is rough average for quite clean DVavi and very good x264 encoder. So you perhaps would not set bitrate that tight, give it i bit more, especially if not deinterlacing. You should get compression 8:1 or 7:1 compressions or smaller to be sure, roughly speaking. 10:1 seams too much.
If you deinterlace, then it is not good, because you are not using good deinterlacer (like QTGMC), you mess up content anyway and it does not matter what bitrate you set.

Interlace content should give a little bit more bitrate (even if it is interlace, that is nature of using QTGMC)

Check x264 encoder and constant rate factor settings, --crf, then you can set quality, not bitrate.

And yes, KEEP those originals

[ColMac]

Sorry Just opened this today, I'll read and respond later.

Thanks