[PATCH] typefinding: extend AAC typefinder for LOAS stream
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[PATCH] typefinding: extend AAC typefinder for LOAS stream
 
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Signed-off-by: Andrzej K. Haczewski <[hidden email]> --- gst/typefind/gsttypefindfunctions.c | 54 +++++++++++++++++++++++++++++++++- 1 files changed, 52 insertions(+), 2 deletions(-) Hello all, Here's a little patch to detect LOAS MPEG-4 streams that carry AAC. I also included additional file extensions for AAC. As the original typefind name did not reflect the new capability, I also altered it to better reflect its purpose, as it is currently capable of detecting any type of stream that AAC can be natively transported in. Feel free to review and comment. Regards, Andrzej K. Haczewski diff --git a/gst/typefind/gsttypefindfunctions.c b/gst/typefind/gsttypefindfunctions.c index 07d8747..25c08fc 100644 --- a/gst/typefind/gsttypefindfunctions.c +++ b/gst/typefind/gsttypefindfunctions.c @@ -679,6 +679,8 @@ aac_type_find (GstTypeFind * tf, gpointer unused) * again a valid syncpoint on the next one (28 bits) for certainty. We * require 4 kB, which is quite a lot, since frames are generally 200-400 * bytes. + * LOAS has 2 possible syncwords, which are 11 bits and 16 bits long. + * The following stream syntax depends on which one is found. */ if (G_UNLIKELY (!data_scan_ctx_ensure_data (tf, &c, 6))) break; @@ -756,6 +758,54 @@ aac_type_find (GstTypeFind * tf, gpointer unused) } GST_DEBUG ("No next frame found... (should have been at 0x%x)", len); + } else if (G_UNLIKELY (((snc & 0xffe0) == 0x56e0) || (snc == 0x4de1))) { + /* LOAS frame */ + + GST_DEBUG ("Found one LOAS syncword at offset 0x%" G_GINT64_MODIFIER + "x, tracing next...", c.offset); + + /* check length of frame for each type of detectable LOAS streams */ + if (snc == 0x4de1) { + /* EPAudioSyncStream */ + len = ((c.data[2] & 0x0f) << 9) | (c.data[3] << 1) | + ((c.data[4] & 0x80) >> 7); + /* add size of EP sync stream header */ + len += 7; + } else { + /* AudioSyncStream */ + len = ((c.data[1] & 0x1f) << 8) | c.data[2]; + /* add size of sync stream header */ + len += 3; + } + + if (len == 0 || !data_scan_ctx_ensure_data (tf, &c, len + 2)) { + GST_DEBUG ("Wrong sync or next frame not within reach, len=%u", len); + goto next; + } + + /* check if there's a second LOAS frame */ + snc = GST_READ_UINT16_BE (c.data + len); + if (((snc & 0xffe0) == 0x56e0) || (snc == 0x4de1)) { + GstCaps *caps; + + GST_DEBUG ("Found second LOAS syncword at offset 0x%" + G_GINT64_MODIFIER "x, framelen %u", c.offset, len); + + /* Set additional field to indicate which type of LOAS stream is found. + * It is purely informational field as receiving element have to parse + * the stream anyway. */ + caps = gst_caps_new_simple ("audio/mpeg", + "framed", G_TYPE_BOOLEAN, FALSE, + "mpegversion", G_TYPE_INT, 4, + "stream-type", G_TYPE_STRING, "loas", + "error-resilient", G_TYPE_BOOLEAN, (snc == 0x4de1), NULL); + + gst_type_find_suggest (tf, GST_TYPE_FIND_LIKELY, caps); + gst_caps_unref (caps); + break; + } + + GST_DEBUG ("No next frame found... (should have been at 0x%x)", len); } else if (!memcmp (c.data, "ADIF", 4)) { /* ADIF header */ gst_type_find_suggest_simple (tf, GST_TYPE_FIND_LIKELY, "audio/mpeg", @@ -3923,7 +3973,7 @@ plugin_init (GstPlugin * plugin) static const gchar *compress_exts[] = { "Z", NULL }; static const gchar *m4a_exts[] = { "m4a", NULL }; static const gchar *q3gp_exts[] = { "3gp", NULL }; - static const gchar *aac_exts[] = { "aac", NULL }; + static const gchar *aac_exts[] = { "aac", "adts", "adif", "loas", NULL }; static const gchar *spc_exts[] = { "spc", NULL }; static const gchar *wavpack_exts[] = { "wv", "wvp", NULL }; static const gchar *wavpack_correction_exts[] = { "wvc", NULL }; @@ -4156,7 +4206,7 @@ plugin_init (GstPlugin * plugin) NULL, CMML_CAPS, NULL, NULL); TYPE_FIND_REGISTER_START_WITH (plugin, "application/x-executable", GST_RANK_MARGINAL, NULL, "\177ELF", 4, GST_TYPE_FIND_MAXIMUM); - TYPE_FIND_REGISTER (plugin, "adts_mpeg_stream", GST_RANK_SECONDARY, + TYPE_FIND_REGISTER (plugin, "audio/aac", GST_RANK_SECONDARY, aac_type_find, aac_exts, AAC_CAPS, NULL, NULL); TYPE_FIND_REGISTER_START_WITH (plugin, "audio/x-spc", GST_RANK_SECONDARY, spc_exts, "SNES-SPC700 Sound File Data", 27, GST_TYPE_FIND_MAXIMUM); -- 1.7.1 ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/gstreamer-devel |
Re: [PATCH] typefinding: extend AAC typefinder for LOAS stream
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Hello,
You might be interested in this thread: https://bugzilla.gnome.org/show_bug.cgi?id=615740
On Thu, Jul 8, 2010 at 10:43 AM, Andrzej K. Haczewski <[hidden email]> wrote:
-- André Dieb Martins ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/gstreamer-devel |
Re: [PATCH] typefinding: extend AAC typefinder for LOAS stream
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In reply to this post by Andrzej K. Haczewski
On Thu, 2010-07-08 at 15:43 +0200, Andrzej K. Haczewski wrote:
> Here's a little patch to detect LOAS MPEG-4 streams that carry AAC. Great, but could you please put that into bugzilla so we don't forget about it, -base is currently frozen for commits. Thanks! http://gstreamer.freedesktop.org/bugs/ Cheers -Tim ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/gstreamer-devel |
Re: [PATCH] typefinding: extend AAC typefinder for LOAS stream
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2010/7/9 Tim-Philipp Müller <[hidden email]>:
> On Thu, 2010-07-08 at 15:43 +0200, Andrzej K. Haczewski wrote: > >> Here's a little patch to detect LOAS MPEG-4 streams that carry AAC. > > Great, but could you please put that into bugzilla so we don't forget > about it, -base is currently frozen for commits. Thanks! > > http://gstreamer.freedesktop.org/bugs/ > There you go: https://bugzilla.gnome.org/show_bug.cgi?id=623918 Thanks, Andrew ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/gstreamer-devel |
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