best DVD to AVI encoding

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  • ThraxThrax 🐌 Austin, TX Icrontian
    edited August 2008
    stoopid wrote:
    Okay, I'm back with my tail between my legs :(.

    I have learned that the playback device I'm using (Sansa Fuze) plays at 20fps! This explains my issues I believe, because even with a properly encoded AVI file the audio still falls out of sync when put through the Sansa converter. Then I looked online and discovered I'm not alone and everyone using the utility is having similar issues. Before I was not getting my conversion to work properly before even sending the AVI through the Sansa media converter. Now I have perfectly generated AVI files, but I'm only 50% there it seems.

    So I tried Super again and set the output type to AVI with MP4 decoding and MP3 audio, video at 224x176 resolution (supposedly what the player uses) with 20fps. I removed the 48khz audio flag set by default and left it on high quality. The audio is set to 44.1 128kbps MP3 with auto/default audio track selection. The file attempts to convert and fails before finishing. The error in Super is always the same generic one (useless/non-specific).

    The good news is that unlike before, I can copy/paste the almost converted AVI onto the memory card with out an error. Before if I tried to copy just any old AVI it would popup a window alert that the file type is unsupported by the device and asked if I wanted to copy anyway. Unfortunately it still doesn't playback on the device (says it's unsupported), but that may just be a result of the file being unfinished/corrputed.

    One question I have is conversion to a non-standard format like 20fps. Is this really possible? Won't I always have problems getting NTSC encoded files to convert to this?

    No. The source material is 23.976 FPS, and being compressed down to 20 FPS. You're losing almost 4 frames a second, which means the over all movie will have a shorter run time than advertised. To compensate, converters will compress the run time of the audio as well. As a result, the audio will be pitch-shifted upwards (about a quarter octave) to accommodate.
  • stoopidstoopid Albany, NY New
    edited August 2008
    Thrax wrote:
    No. The source material is 23.976 FPS, and being compressed down to 20 FPS. You're losing almost 4 frames a second, which means the over all movie will have a shorter run time than advertised. To compensate, converters will compress the run time of the audio as well. As a result, the audio will be pitch-shifted upwards (about a quarter octave) to accommodate.

    What about transcoding? Split the video and audio tracks, then re-encode then together?

    If I do the conversion of a working AVI through the Sansa encoder it's doing the 20fps conversion without pitch shifting (quarter octave would be noticeable). Just starts losing sync after 10 minutes, and gets pretty bad by the end of the Sansa encoded file. Same issue when I encode my own AVIs. I'm trying to figure out whether the video or audio are being incorrectly converted/analyzed, which gives me a starting point as to what settings to tinker with first. Or possibly I have some incompatible codecs?
  • ThraxThrax 🐌 Austin, TX Icrontian
    edited August 2008
    If you're upconverting the FPS or downconverting the FPS, you will get pitch-shifted audio. There's no way around it. When you compress the wavelength to a new timescale, the frequency of the waves increases and you get higher-pitched audio. There are some processing tricks that try and compensate for it, but they all have various levels of success.

    Few people actually notice the octave shift because they have nothing to compare the shifted material against. A quarter octave actually isn't a whole lot.

    Most conversion programs split the audio and video streams and encode them separately. AutoGK uses BeSweet and LAME for audio processing (Both are regarded as the world's best for this), then AVISynth for frameserving the video. Ideal choices. The resultant files are then muxed back together because they were reencoded on the same timescale.
  • zero-counterzero-counter Linux Lubber San Antonio Member
    edited August 2008
    stoopid wrote:
    I'm the proud new owner of my first full fledged MP3/MP4 player (sansa fuze, 8GB). I bought an additional 8GB microsd so I can bring a few videos with me in case I get tired of music. I've successfully made MP4 from DVDs using the utility they supply, but it saves the MP4s as separate files (because you encode the VOBs to MP4s). I'm thinking of encoding to AVI then making a single MP4 from that. Thoughts?

    DVDfab sounds like it may be your tool of choice. With compatible IPOD presets, it will rip/decrypt/convert/mux the movies, has a clean interface, a small footprint, and has the same "set it and forget it" capabilities as others. You can crop the video as well. This one is more "user friendly" than many others out there, IMHO.

    I wouldn't discount Handbrake over Gordian Knot. They each have their specific uses and advantages/disadvantages about them as well. There are presets and some have reported that the IPOD preset works with the Sansas. Not quite sure what happened to your run through but if you post the logfile to the handbrake forums, the guys there can help if you want to continue that way.

    BTW Thrax, the quarter octave comment is purely subjective and varies across listeners. Varied intonation is the usual result and is noticeable to many, especially those with perfect pitch hearing.

    Just remember...to each their own! :bigggrin:
  • stoopidstoopid Albany, NY New
    edited August 2008
    It's also a music DVD (live show) that I'm trying to encode, of material I'm very familiar with. But I have far from perfect pitch so there's always the possibility that I can't tell.

    Someone else recommended DVDfab for another reason but I've seen and heard good things. I'm willing to give it a shot. All other roads, based on my googlingm, are dead-ends at the moment. My best option at the moment with the Sansa media convert software is to encode the VOBs seperately so the sync issue is only a minor issue after 20-30 minutes before the next VOB starts (and restarts the synchronization). I don't really find that acceptible, but Sansa hasn't fixed this issue since it was first reported a couple years ago with their e2XX series players.

    Thanks again guys for expanding my knowledge on the subject and trying to give me some easier solutions to try.
  • stoopidstoopid Albany, NY New
    edited August 2008
    I think we have a winner. DVDfab offers a lot of presets, and while none of them work if I directly drop them onto the device, the option to create an AVI from each chapter has minimized the length of the individual files. Even if there's still a sync issue it doesn't show up in the 10 minutes or so each chapter runs. Not a solution but an acceptible work around. Thanks! :)
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