On Fri, Jul 31, 2015 at 8:08 PM, Michael Niedermayer <mich...@niedermayer.cc> wrote: > On Fri, Jul 31, 2015 at 07:33:01PM -0400, Ganesh Ajjanagadde wrote: >> On Fri, Jul 31, 2015 at 7:01 PM, Ihar A. Tumashyk <itumas...@gmail.com> >> wrote: >> > Sample rate is written "as is" in header . Is *should not* be devined by >> > 8. Refer spec.: >> > http://dsd-guide.com/sites/default/files/white- >> > papers/DSFFileFormatSpec_E.pdf >> > >> > After this patch ffprobe will corretly show sample rate for DSF files. >> > >> > Signed-off-by: Ihar A. Tumashyk <itumas...@gmail.com> >> > --- >> > libavformat/dsfdec.c | 2 +- >> > 1 file changed, 1 insertion(+), 1 deletion(-) >> > >> > diff --git a/libavformat/dsfdec.c b/libavformat/dsfdec.c >> > index ae198b2..3e162ae 100644 >> > --- a/libavformat/dsfdec.c >> > +++ b/libavformat/dsfdec.c >> > @@ -105,7 +105,7 @@ static int dsf_read_header(AVFormatContext *s) >> > >> > st->codec->codec_type = AVMEDIA_TYPE_AUDIO; >> > st->codec->channels = avio_rl32(pb); >> > - st->codec->sample_rate = avio_rl32(pb) / 8; >> > + st->codec->sample_rate = avio_rl32(pb); >> > >> > switch(avio_rl32(pb)) { >> > case 1: st->codec->codec_id = AV_CODEC_ID_DSD_LSBF_PLANAR; break; >> >> LGTM, thanks for clarifying intent of previous patch. >> I am a little puzzled as to why this was never caught till now, > > Changing the sample rate like in the patch breaks playback (it plays > much too quick) > you can find samples to test at: > http://www.2l.no/hires/
I really need to stop trusting these spec files that much, they are often incomplete as in this case. Ironically, wikipedia here gives a much better description of the format: https://en.wikipedia.org/wiki/Direct_Stream_Digital, where they mention that essentially this signal is oversampled by a factor of 8. As the wiki entry indicates, max frequency of PCM is 352.8 kHz. In fact, I think previous patch should be reverted: the wikipedia article says that newer format is called "DSD-wide" and uses 8-bit word length. ffprobe yields the downsampled frequency of 352.8 kHz which is what actually gets used when one demuxes/ operates on the data per wikipedia. Thus, I believe previous behavior was correct. > > [...] > > -- > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB > > In fact, the RIAA has been known to suggest that students drop out > of college or go to community college in order to be able to afford > settlements. -- The RIAA > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
