Flash video to MPG-2: bit rate?

[am_dew]

I have a bunch of .F4V (Flash Video) files with the following properties per MediaInfo that I am going to convert to DVD complaint MPEG-2 files using TMPGEnc Express and then eventually author a DVD from the MPG-2 files.

Am I wasting my time by using a VBR bit-rate of 6000 Kbps when encoding to MPEG-2? In other words, can I use, say a bit-rate of 3000 without any quality loss?

Thanks!

Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 49.3 MiB
Duration : 4mn 55s
Overall bit rate : 1 400 Kbps
Encoded date : UTC 2011-08-18 00:43:57
Tagged date : UTC 2011-08-18 00:43:57
Writing library : Apple QuickTime

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.1
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 4mn 55s
Bit rate mode : Variable
Bit rate : 1 144 Kbps
Maximum bit rate : 1 200 Kbps
Width : 854 pixels
Height : 480 pixels
Display aspect ratio : 16:9
Original display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 fps
Standard : Component
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.093
Stream size : 40.3 MiB (82%)
Language : English
Encoded date : UTC 2011-08-18 00:43:57
Tagged date : UTC 2011-08-18 00:43:57
Material_Duration : 295529
Material_StreamSize : 44470238
Material_FrameCount : 8857

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 4mn 55s
Bit rate mode : Variable
Bit rate : 192 Kbps
Maximum bit rate : 201 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 KHz
Compression mode : Lossy
Stream size : 6.77 MiB (14%)
Language : English
Encoded date : UTC 2011-08-18 00:43:57
Tagged date : UTC 2011-08-18 00:43:57

[DoubleYou]

Since the highest bit rate of all the video files you mention is 400kbps, I think you should easily get away with a bitrate of 3000kbps or even less. However, since your video files are rather small and of rather poor quality, I wonder why you want to convert them to make a DVD. Are you just trying to change your flash video files into an editable format so you can, like, make a DVD with them in Windows Movie Maker or something? If so, your best bet rather than encoding and then re-encoding to DVD would be to extract and remux first and only encode on the last step.

[am_dew]

Thanks for the reply.

I believe the bit rate on these files is 1400, not 400...MediaInfo seems to always put a space after the first digit in the bit rate field for some reason.

In any case, yes I would like to make a DVD out of them. I have done so with similar F4V files and you'd be surprised at how good they look on DVD despite the relatively low bit rate source.

My tool of choice to get the files ready for DVD is TMPGEnc Express 4, in which I am applying a few filters and doing a small bit of editing. Then I use TMPGEnc DVD Author to create the final DVD from the output files I get from Express. Because the MPEG-2 output files I get from Express are already DVD compliant, DVD Author uses "Smart Rendering" on them so I am pretty sure the files do not get fully re-encoded again.

[DoubleYou]

Actually, since the video is encoded to AVC, I do not doubt that the quality does turn out remarkable for the low bitrate, making you think there is an inaccuracy in the bitrate estimation by mediainfo. AVC is known for producing high quality video at low bitrates, and therefore lower filesizes, making it highly viable for web video and movie cameras. I have seen extremely well-done web videos encoded at a bitrate of 100kbps and still look reasonably great. And TVs often make DVDs look better than they do on your computer. By the way, do you use the GUI for MediaInfo or the command prompt version?

I have not worked with TMPGEnc Express, so I don't know how it would work, but I would think it actually make little time difference encoding at 3000kbps versus 6000kbps because of the bitrate ceiling imposed by the original video's low bitrate. I'd suggest that you test them. Convert at both bitrates and compare in mediainfo. If the bitrates aren't much different, you'll know that you've hit the ceiling. If such is the case, there probably is little difference in whichever bitrate you choose to encode at. Often I'll take a 600kbps AVC video and encode it at a setting of 9000kbps to ensure no quality loss, and it normally comes out at a ceiling bitrate of maybe 1500kbps even though set at 9000kbps. Hope this helps. I doubt that a bitrate of 3000kbps would reduce the quality too much at all.

[am_dew]

These files I am working are web streaming files (archived live music concert video). I think I will just encode them at 6000 and be done with it. I have done some testing at that bit rate and my MPG files look as good to my eye as the original F4V files look. Using that rate I can fit (single sided DVD) 80+ minutes of video and also use a better alternate audio source, which is a large WAV file (which I have I done some remastering to in order to sweeten it up a bit) which was extracted from the original F4V files.

Thanks for your help...much appreciated!

[DoubleYou]

Good luck and I hope you don't have too many audio-video sync issues with the alternate audio

[am_dew]

Thanks. No audio-video synch issues at all. My alternate audio source uses the same exact TMPGEnc Express project file I used to output the MPEG-2 files from the F4V files except I temporarily change the output to WAV instead of MPEG-2. So I end up with the same cut-edits in the audio as I have in the video. In this project's case, the audio EXACTLY matches the video in length to the millisecond. For the simple DVD projects I do that require format conversions, I really like TMPGEnc Express 4. Mind you, I am not a pro at this, just someone who enjoys making DVDs from various content I come across, which otherwise would only be available via web streaming. But, I think I do pretty well, all things considered and have some very nice DVDs to show for my efforts.