Slow audio in Handbrake

Question

I was trying to convert a H264 video down to iPod resolution in order to be able to watch on my Palm Pre. It turns out that while video converts just fine, the audio track seems to be dramatically slowed down. I have tested this with both 0.9.3 and svn2907 with similar results.

Looking around, it seems that while there are similar reports, there have been no resolutions. FWIW, this is on Snow Leopard running 10.6.1.

The output is as follows:

[23:52:14] hb_init: checking cpu count
[23:52:14] hb_init: starting libhb thread
HandBrake svn2907 (2009110101) - Darwin x86_64 - http://handbrake.fr
2 CPUs detected
Opening sample.mp4...
[23:52:14] hb_scan: path=sample.mp4, title_index=1
[23:52:14] scan: trying to open with libdvdread
libdvdnav: Using dvdnav version 4.1.3
libdvdread: Using libdvdcss version 1.2.10 for DVD access
libdvdnav:DVDOpenFileUDF:UDFFindFile /VIDEO_TS/VIDEO_TS.IFO failed
libdvdnav:DVDOpenFileUDF:UDFFindFile /VIDEO_TS/VIDEO_TS.BUP failed
libdvdread: Can't open file VIDEO_TS.IFO.
libdvdnav: vm: failed to read VIDEO_TS.IFO
[23:52:15] dvd: not a dvd - trying as a stream/file instead
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'sample.mp4':
  Duration: 00:00:58.89, start: 0.000000, bitrate: 1668 kb/s
    Stream #0.0(und): Video: h264, yuv420p, 1280x544 [PAR 1:1 DAR 40:17], 23.98 tbr, 23.98 tbn, 47.95 tbc
    Stream #0.1(und): Audio: aac, 48000 Hz, 5.1, s16
[23:52:15] scan: decoding previews for title 1
Scanning title 1...
Scanning title 1...
Scanning title 1...
Scanning title 1...
Scanning title 1...
[23:52:16] scan: 10 previews, 1280x544, 23.976 fps, autocrop = 0/0/0/0, aspect 2.35:1, PAR 1:1
[23:52:16] scan: title (0) job->width:1280, job->height:544
[23:52:16] libhb: scan thread found 1 valid title(s)
+ title 1:
  + vts 0, ttn 0, cells 0->0 (0 blocks)
  + angle(s) 0
  + duration: 00:00:58
  + size: 1280x544, pixel aspect: 1/1, display aspect: 2.35, 23.976 fps
  + autocrop: 0/0/0/0
  + chapters:
    + 1: cells 0->0, 0 blocks, duration 00:00:58
  + audio tracks:
    + 1, Unknown (AAC) (iso639-2: und)
  + subtitle tracks:
[23:52:17] 1 job(s) to process
[23:52:17] starting job
[23:52:17] work: sanitizing track 0 mixdown Dolby Pro Logic II to Stereo
[23:52:17] job configuration:
[23:52:17]  * source
[23:52:17]    + sample.mp4
[23:52:17]    + title 1, chapter(s) 1 to 1
[23:52:17]    + container: mov,mp4,m4a,3gp,3g2,mj2
[23:52:17]    + data rate: 1668 kbps
[23:52:17]  * destination
[23:52:17]    + foo.mp4
[23:52:17]    + container: MPEG-4 (.mp4 and .m4v)
[23:52:17]  * video track
[23:52:17]    + decoder: h264
[23:52:17]    + frame rate: same as source (around 23.976 fps)
[23:52:17]    + dimensions: 1280 * 544 -> 480 * 320, crop 0/0/0/0
[23:52:17]    + encoder: FFmpeg
[23:52:17]      + bitrate: 1000 kbps, pass: 0
[23:52:17]  * audio track 0
[23:52:17]    + decoder: Unknown (AAC) (track 1, id 1)
[23:52:17]    + mixdown: Stereo
[23:52:17]    + encoder: faac
[23:52:17]      + bitrate: 160 kbps, samplerate: 48000 Hz
libdvdnav: Using dvdnav version 4.1.3
libdvdread: Using libdvdcss version 1.2.10 for DVD access
libdvdnav:DVDOpenFileUDF:UDFFindFile /VIDEO_TS/VIDEO_TS.IFO failed
libdvdnav:DVDOpenFileUDF:UDFFindFile /VIDEO_TS/VIDEO_TS.BUP failed
libdvdread: Can't open file VIDEO_TS.IFO.
libdvdnav: vm: failed to read VIDEO_TS.IFO
[23:52:17] dvd: not a dvd - trying as a stream/file instead
[23:52:17] reader: first SCR 3753 id 0 DTS 0
[23:52:17] sync: expecting 1435 video frames
Encoding: task 1 of 1, 0.00 %[23:52:17] sync: first pts is 3753
Encoding: task 1 of 1, 95.05 % (33.21 fps, avg 35.73 fps, ETA 00h00m02s)[23:52:56] reader: done. 1 scr changes
Encoding: task 1 of 1, 96.72 % (34.55 fps, avg 35.52 fps, ETA 00h00m01s)[23:52:56] sync: got 1410 frames, 1435 expected
[23:52:56] work: average encoding speed for job is 35.522232 fps
Encoding: task 1 of 1, 98.26 % (34.55 fps, avg 35.52 fps, ETA 00h00m01s)[23:52:58] mux: track 0, 1410 frames, 5452132 bytes, 247.05 kbps, fifo 8
[23:52:58] mux: track 1, 8275 frames, 3522495 bytes, 159.61 kbps, fifo 8192
[23:52:58] h264-decoder done: 1411 frames, 0 decoder errors, 0 drops
[23:52:58] render: lost time: 0 (0 frames)
[23:52:58] render: gained time: 0 (0 frames) (0 not accounted for)
[23:52:58] aac-decoder done: 0 frames, 0 decoder errors, 0 drops
[23:52:58] libhb: work result = 0

Answer 1

A bit drastic but what I've done before (with success) is extract the audio from the video (you can use garageband - drag video file in, delete video track, export audio), then try to re-encode the video, importing the audio separately to recombine them.

Answer 2

Have you tried with a CBR audio source? this happened to be and after some testing that this stereo source to mono conversion only seems to be the case when with a VBR source. I tried with a CBR audio source and there is no slow-mo audio

Answer 3

What happens when you change the audio settings (try another format, another bitrate, …) for the output file ?

Answer 4

If you leave the Mixdown as "Dolby Pro Logic II" (As opposed to Stereo) in the "Audio & Subtitles" tab does this still happen? I have heard of this HandBrake problem before but usually the bug was related to a Mixdown of "Mono". Give this a try and report back.