From 0d5b5d839a3fb92620bdc90579eab9192a74df3a Mon Sep 17 00:00:00 2001 From: Mark Nauwelaerts Date: Tue, 21 Feb 2012 18:42:31 +0100 Subject: [PATCH] mpegaudioparse: support parsing freeform bitrate stream --- gst/audioparsers/gstmpegaudioparse.c | 168 ++++++++++++++++++++++++--- gst/audioparsers/gstmpegaudioparse.h | 2 + 2 files changed, 156 insertions(+), 14 deletions(-) diff --git a/gst/audioparsers/gstmpegaudioparse.c b/gst/audioparsers/gstmpegaudioparse.c index efb97587ad..a8c68252c6 100644 --- a/gst/audioparsers/gstmpegaudioparse.c +++ b/gst/audioparsers/gstmpegaudioparse.c @@ -200,6 +200,7 @@ gst_mpeg_audio_parse_reset (GstMpegAudioParse * mp3parse) mp3parse->sent_codec_tag = FALSE; mp3parse->last_posted_crc = CRC_UNKNOWN; mp3parse->last_posted_channel_mode = MPEG_AUDIO_CHANNEL_MODE_UNKNOWN; + mp3parse->freerate = 0; mp3parse->hdr_bitrate = 0; @@ -307,14 +308,16 @@ mp3_type_frame_length_from_header (GstMpegAudioParse * mp3parse, guint32 header, bitrate = (header >> 12) & 0xF; bitrate = mp3types_bitrates[lsf][layer - 1][bitrate] * 1000; - /* The caller has ensured we have a valid header, so bitrate can't be - zero here. */ - g_assert (bitrate != 0); + if (!bitrate) { + GST_LOG_OBJECT (mp3parse, "using freeform bitrate"); + bitrate = mp3parse->freerate; + } samplerate = (header >> 10) & 0x3; samplerate = mp3types_freqs[lsf + mpg25][samplerate]; - padding = (header >> 9) & 0x1; + /* force 0 length if 0 bitrate */ + padding = (bitrate > 0) ? (header >> 9) & 0x1 : 0; mode = (header >> 6) & 0x3; channels = (mode == 3) ? 1 : 2; @@ -419,8 +422,7 @@ gst_mp3parse_validate_extended (GstMpegAudioParse * mp3parse, GstBuffer * buf, (guint) next_header & HDRMASK, bpf); *valid = FALSE; return TRUE; - } else if ((((next_header >> 12) & 0xf) == 0) || - (((next_header >> 12) & 0xf) == 0xf)) { + } else if (((next_header >> 12) & 0xf) == 0xf) { /* The essential parts were the same, but the bitrate held an invalid value - also reject */ GST_DEBUG_OBJECT (mp3parse, "next header invalid (bitrate)"); @@ -431,6 +433,13 @@ gst_mp3parse_validate_extended (GstMpegAudioParse * mp3parse, GstBuffer * buf, bpf = mp3_type_frame_length_from_header (mp3parse, next_header, NULL, NULL, NULL, NULL, NULL, NULL, NULL); + /* if no bitrate, and no freeform rate known, then fail */ + if (G_UNLIKELY (!bpf)) { + GST_DEBUG_OBJECT (mp3parse, "next header invalid (bitrate 0)"); + *valid = FALSE; + return TRUE; + } + offset += bpf; frames_found++; } @@ -461,11 +470,6 @@ gst_mpeg_audio_parse_head_check (GstMpegAudioParse * mp3parse, return FALSE; } /* if it's an invalid bitrate */ - if (((head >> 12) & 0xf) == 0x0) { - GST_WARNING_OBJECT (mp3parse, "invalid bitrate: 0x%lx." - "Free format files are not supported yet", (head >> 12) & 0xf); - return FALSE; - } if (((head >> 12) & 0xf) == 0xf) { GST_WARNING_OBJECT (mp3parse, "invalid bitrate: 0x%lx", (head >> 12) & 0xf); return FALSE; @@ -486,6 +490,115 @@ gst_mpeg_audio_parse_head_check (GstMpegAudioParse * mp3parse, return TRUE; } +/* Determines possible freeform frame rate/size by looking for next + * header with valid bitrate (0 or otherwise valid) (and sufficiently + * matching current header). + * + * Returns TRUE if we've found such one, and *rate then contains rate + * (or *rate contains 0 if decided no freeframe size could be determined). + * If not enough data, returns FALSE. + */ +static gboolean +gst_mp3parse_find_freerate (GstMpegAudioParse * mp3parse, GstBuffer * buf, + guint32 header, gboolean at_eos, gint * _rate) +{ + guint32 next_header; + const guint8 *data; + guint available; + int offset = 4; + gulong samplerate, rate, layer, padding; + gboolean valid; + gint lsf, mpg25; + + available = GST_BUFFER_SIZE (buf); + data = GST_BUFFER_DATA (buf); + + *_rate = 0; + + /* pick apart header again partially */ + if (header & (1 << 20)) { + lsf = (header & (1 << 19)) ? 0 : 1; + mpg25 = 0; + } else { + lsf = 1; + mpg25 = 1; + } + layer = 4 - ((header >> 17) & 0x3); + samplerate = (header >> 10) & 0x3; + samplerate = mp3types_freqs[lsf + mpg25][samplerate]; + padding = (header >> 9) & 0x1; + + for (; offset < available; ++offset) { + /* Check if we have enough data for all these frames, plus the next + frame header. */ + if (available < offset + 4) { + if (at_eos) { + /* Running out of data; failed to determine size */ + return TRUE; + } else { + return FALSE; + } + } + + valid = FALSE; + next_header = GST_READ_UINT32_BE (data + offset); + if ((next_header & 0xFFE00000) != 0xFFE00000) + goto next; + + GST_DEBUG_OBJECT (mp3parse, "At %d: header=%08X, header2=%08X", + offset, (unsigned int) header, (unsigned int) next_header); + + if ((next_header & HDRMASK) != (header & HDRMASK)) { + /* If any of the unmasked bits don't match, then it's not valid */ + GST_DEBUG_OBJECT (mp3parse, "next header doesn't match " + "(header=%08X (%08X), header2=%08X (%08X))", + (guint) header, (guint) header & HDRMASK, (guint) next_header, + (guint) next_header & HDRMASK); + goto next; + } else if (((next_header >> 12) & 0xf) == 0xf) { + /* The essential parts were the same, but the bitrate held an + invalid value - also reject */ + GST_DEBUG_OBJECT (mp3parse, "next header invalid (bitrate)"); + goto next; + } + + valid = TRUE; + + next: + /* almost accept as free frame */ + if (layer == 1) { + rate = samplerate * (offset - 4 * padding + 4) / 48000; + } else { + rate = samplerate * (offset - padding + 1) / (144 >> lsf) / 1000; + } + + if (valid) { + GST_LOG_OBJECT (mp3parse, "calculated rate %d", rate * 1000); + if (rate < 8 || (layer == 3 && rate > 640)) { + GST_DEBUG_OBJECT (mp3parse, "rate invalid"); + if (rate < 8) { + /* maybe some hope */ + continue; + } else { + GST_DEBUG_OBJECT (mp3parse, "aborting"); + /* give up */ + break; + } + } + *_rate = rate * 1000; + break; + } else { + /* avoid indefinite searching */ + if (rate > 1000) { + GST_DEBUG_OBJECT (mp3parse, "exceeded sanity rate; aborting"); + break; + } + } + } + + return TRUE; +} + static gboolean gst_mpeg_audio_parse_check_valid_frame (GstBaseParse * parse, GstBaseParseFrame * frame, guint * framesize, gint * skipsize) @@ -527,9 +640,14 @@ gst_mpeg_audio_parse_check_valid_frame (GstBaseParse * parse, GST_LOG_OBJECT (parse, "got frame"); + lost_sync = GST_BASE_PARSE_LOST_SYNC (parse); + draining = GST_BASE_PARSE_DRAINING (parse); + + if (G_UNLIKELY (lost_sync)) + mp3parse->freerate = 0; + bpf = mp3_type_frame_length_from_header (mp3parse, header, &version, &layer, &channels, &bitrate, &rate, &mode, &crc); - g_assert (bpf != 0); if (channels != mp3parse->channels || rate != mp3parse->rate || layer != mp3parse->layer || version != mp3parse->version) @@ -537,8 +655,30 @@ gst_mpeg_audio_parse_check_valid_frame (GstBaseParse * parse, else caps_change = FALSE; - lost_sync = GST_BASE_PARSE_LOST_SYNC (parse); - draining = GST_BASE_PARSE_DRAINING (parse); + /* maybe free format */ + if (bpf == 0) { + GST_LOG_OBJECT (mp3parse, "possibly free format"); + if (lost_sync || mp3parse->freerate == 0) { + GST_DEBUG_OBJECT (mp3parse, "finding free format rate"); + if (!gst_mp3parse_find_freerate (mp3parse, buf, header, draining, &valid)) { + /* not enough data */ + *framesize = G_MAXUINT; + *skipsize = 0; + return FALSE; + } else { + GST_DEBUG_OBJECT (parse, "determined freeform size %d", valid); + mp3parse->freerate = valid; + } + } + /* try again */ + bpf = mp3_type_frame_length_from_header (mp3parse, header, + &version, &layer, &channels, &bitrate, &rate, &mode, &crc); + if (!bpf) { + /* did not come up with valid freeform length, reject after all */ + *skipsize = 1; + return FALSE; + } + } if (!draining && (lost_sync || caps_change)) { if (!gst_mp3parse_validate_extended (mp3parse, buf, header, bpf, draining, diff --git a/gst/audioparsers/gstmpegaudioparse.h b/gst/audioparsers/gstmpegaudioparse.h index 7580001309..6b42673552 100644 --- a/gst/audioparsers/gstmpegaudioparse.h +++ b/gst/audioparsers/gstmpegaudioparse.h @@ -60,6 +60,8 @@ struct _GstMpegAudioParse { /* samples per frame */ gint spf; + gint freerate; + gboolean sent_codec_tag; guint last_posted_bitrate; gint last_posted_crc, last_crc;