/* GStreamer * Copyright (C) <2007> Jan Schmidt * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include /* The purpose of the packetiser is to parse the incoming buffers into 'blocks' * that consist of the stream split at certain packet boundaries. It splits into * a new block at the start of a GOP, Picture or Sequence packet. * A GOP or sequence header always starts a new block. A Picture * header starts a new block only if the previous packet was not a GOP - * otherwise it is accumulated with the GOP */ #include "mpegpacketiser.h" static void collect_packets (MPEGPacketiser * p, GstBuffer * buf); void mpeg_packetiser_init (MPEGPacketiser * p) { p->adapter = gst_adapter_new (); p->n_blocks = 0; p->blocks = NULL; mpeg_packetiser_flush (p); } void mpeg_packetiser_free (MPEGPacketiser * p) { g_object_unref (p->adapter); g_free (p->blocks); } void mpeg_packetiser_add_buf (MPEGPacketiser * p, GstBuffer * buf) { /* Add the buffer to our pool */ gst_adapter_push (p->adapter, buf); /* Store the timestamp to apply to the next picture that gets collected */ if (p->cur_buf_ts != GST_CLOCK_TIME_NONE) { p->prev_buf_ts = p->cur_buf_ts; } p->cur_buf_ts = GST_BUFFER_TIMESTAMP (buf); /* read what new packets we have in this buffer */ collect_packets (p, buf); p->tracked_offset += GST_BUFFER_SIZE (buf); } void mpeg_packetiser_flush (MPEGPacketiser * p) { gst_adapter_clear (p->adapter); p->adapter_offset = 0; p->sync_word = 0xffffffff; p->tracked_offset = 0; p->prev_sync_packet = MPEG_PACKET_NONE; /* Reset our block info */ p->cur_block_idx = -1; p->first_block_idx = -1; /* Clear any pending timestamps */ p->prev_buf_ts = GST_CLOCK_TIME_NONE; p->cur_buf_ts = GST_CLOCK_TIME_NONE; } guint8 * mpeg_util_find_start_code (guint32 * sync_word, guint8 * cur, guint8 * end) { guint32 code; if (G_UNLIKELY (cur == NULL)) return NULL; code = *sync_word; while (cur < end) { code <<= 8; if (code == 0x00000100) { /* Reset the sync word accumulator */ *sync_word = 0xffffffff; return cur; } /* Add the next available byte to the collected sync word */ code |= *cur++; } *sync_word = code; return NULL; } /* When we need to reallocate the blocks array, grow it by this much */ #define BLOCKS_INCREMENT 5 /* Get the index of the next unfilled block in the buffer. May need to grow * the array first */ static gint get_next_free_block (MPEGPacketiser * p) { gint next; gboolean grow_array = FALSE; /* Get a free block from the blocks array. May need to grow * the array first */ if (p->n_blocks == 0) { grow_array = TRUE; next = 0; } else { if (G_UNLIKELY (p->cur_block_idx == -1)) { next = 0; } else { next = p->cur_block_idx; if (((next + 1) % p->n_blocks) == p->first_block_idx) grow_array = TRUE; } } if (grow_array) { gint old_n_blocks = p->n_blocks; p->n_blocks += BLOCKS_INCREMENT; p->blocks = g_realloc (p->blocks, sizeof (MPEGBlockInfo) * p->n_blocks); /* Now we may need to move some data up to the end of the array, if the * cur_block_idx is before the first_block_idx in the array. */ if (p->cur_block_idx < p->first_block_idx) { #if 0 g_print ("Moving %d blocks from idx %d to idx %d of %d\n", old_n_blocks - p->first_block_idx, p->first_block_idx, p->first_block_idx + BLOCKS_INCREMENT, p->n_blocks); #endif memmove (p->blocks + p->first_block_idx + BLOCKS_INCREMENT, p->blocks + p->first_block_idx, sizeof (MPEGBlockInfo) * (old_n_blocks - p->first_block_idx)); p->first_block_idx += BLOCKS_INCREMENT; } } return next; } /* Mark the current block as complete */ static void complete_current_block (MPEGPacketiser * p, guint64 offset) { MPEGBlockInfo *block; if (G_UNLIKELY (p->cur_block_idx == -1)) return; /* No block is in progress */ /* If we're pointing at the first_block_idx, then we're about to re-complete * a previously completed buffer. Not allowed, because the array should have * been previously expanded to cope via a get_next_free_block call. */ g_assert (p->cur_block_idx != p->first_block_idx); /* Get the appropriate entry from the blocks array */ g_assert (p->blocks != NULL && p->cur_block_idx < p->n_blocks); block = p->blocks + p->cur_block_idx; /* Extend the block length to the current offset */ g_assert (block->offset < offset); block->length = offset - block->offset; #if 0 g_print ("Completed block of type 0x%02x @ offset %" G_GUINT64_FORMAT " with size %u\n", block->first_pack_type, block->offset, block->length); #endif /* If this is the first complete block, set first_block_idx to be this block */ if (p->first_block_idx == -1) p->first_block_idx = p->cur_block_idx; /* Update the statistics regarding the packet we're handling */ if (block->flags & MPEG_BLOCK_FLAG_PICTURE) p->n_pictures++; /* And advance the cur_block_idx ptr to the next slot */ p->cur_block_idx = (p->cur_block_idx + 1) % p->n_blocks; } /* Accumulate the packet up to 'offset' into the current block * (discard if no block is in progress). Update the block info * to indicate what is in it. */ static void append_to_current_block (MPEGPacketiser * p, guint64 offset, guint8 pack_type) { MPEGBlockInfo *block; if (G_UNLIKELY (p->cur_block_idx == -1)) return; /* No block in progress, drop this packet */ /* Get the appropriate entry from the blocks array */ g_assert (p->blocks != NULL && p->cur_block_idx < p->n_blocks); block = p->blocks + p->cur_block_idx; /* Extend the block length to the current offset */ g_assert (block->offset < offset); block->length = offset - block->offset; /* Update flags */ switch (pack_type) { case MPEG_PACKET_SEQUENCE: g_assert (!(block->flags & (MPEG_BLOCK_FLAG_GOP | MPEG_BLOCK_FLAG_PICTURE))); block->flags |= MPEG_BLOCK_FLAG_SEQUENCE; break; case MPEG_PACKET_GOP: block->flags |= MPEG_BLOCK_FLAG_GOP; break; case MPEG_PACKET_PICTURE: block->flags |= MPEG_BLOCK_FLAG_PICTURE; break; default: break; } } static void start_new_block (MPEGPacketiser * p, guint64 offset, guint8 pack_type) { gint block_idx; MPEGBlockInfo *block; /* First, append data up to the start of this block to the current one, but * not including this packet info */ complete_current_block (p, offset); block_idx = get_next_free_block (p); /* FIXME: Retrieve the appropriate entry from the blocks array */ /* Get the appropriate entry from the blocks array */ g_assert (p->blocks != NULL && block_idx < p->n_blocks); block = p->blocks + block_idx; /* Init the block */ block->first_pack_type = pack_type; block->offset = offset; block->ts = GST_CLOCK_TIME_NONE; /* Initially, the length is 0. It grows as we encounter new sync headers */ block->length = 0; switch (pack_type) { case MPEG_PACKET_SEQUENCE: block->flags = MPEG_BLOCK_FLAG_SEQUENCE; break; case MPEG_PACKET_GOP: block->flags = MPEG_BLOCK_FLAG_GOP; break; case MPEG_PACKET_PICTURE: block->flags = MPEG_BLOCK_FLAG_PICTURE; break; default: /* We don't start blocks with other packet types */ g_assert_not_reached (); } /* Make this our current block */ p->cur_block_idx = block_idx; #if 0 g_print ("Started new block in slot %d with first pack 0x%02x @ offset %" G_GUINT64_FORMAT "\n", block_idx, block->first_pack_type, block->offset); #endif } static void handle_packet (MPEGPacketiser * p, guint64 offset, guint8 pack_type) { switch (pack_type) { case MPEG_PACKET_SEQUENCE: case MPEG_PACKET_GOP: /* Start a new block */ start_new_block (p, offset, pack_type); p->prev_sync_packet = pack_type; break; case MPEG_PACKET_PICTURE:{ MPEGBlockInfo *block; GstClockTime ts; /* Start a new block unless the previous sync packet was a GOP */ if (p->prev_sync_packet != MPEG_PACKET_GOP) { start_new_block (p, offset, pack_type); } else { append_to_current_block (p, offset, pack_type); } p->prev_sync_packet = pack_type; /* We have a picture packet, apply any pending timestamp. The logic here * is that the timestamp on any incoming buffer needs to apply to the next * picture packet where the _first_byte_ of the sync word starts after the * packet boundary. We track the ts from the current buffer and a * previous buffer in order to handle this correctly. It would still be * possible to get it wrong if there was a PES packet smaller than 3 bytes * but anyone that does that can suck it. */ if (offset >= p->tracked_offset) { /* sync word started within this buffer - take the cur ts */ ts = p->cur_buf_ts; p->cur_buf_ts = GST_CLOCK_TIME_NONE; p->prev_buf_ts = GST_CLOCK_TIME_NONE; } else { /* sync word started in a previous buffer - take the old ts */ ts = p->prev_buf_ts; p->prev_buf_ts = GST_CLOCK_TIME_NONE; } /* If we didn't drop the packet, set the timestamp on it */ if (G_LIKELY (p->cur_block_idx != -1)) { block = p->blocks + p->cur_block_idx; block->ts = ts; #if 0 g_print ("Picture @ offset %" G_GINT64_FORMAT " has ts %" GST_TIME_FORMAT "\n", block->offset, GST_TIME_ARGS (block->ts)); #endif } break; } default: append_to_current_block (p, offset, pack_type); break; } } static void collect_packets (MPEGPacketiser * p, GstBuffer * buf) { guint8 *cur; guint8 *end = GST_BUFFER_DATA (buf) + GST_BUFFER_SIZE (buf); cur = mpeg_util_find_start_code (&(p->sync_word), GST_BUFFER_DATA (buf), end); while (cur != NULL) { /* Calculate the offset as tracked since the last flush. Note that cur * points to the last byte of the sync word, so we adjust by -3 to get the * first byte */ guint64 offset = p->tracked_offset + (cur - GST_BUFFER_DATA (buf) - 3); handle_packet (p, offset, *cur); cur = mpeg_util_find_start_code (&(p->sync_word), cur, end); } } void mpeg_packetiser_handle_eos (MPEGPacketiser * p) { /* Append any remaining data to the current block */ if (p->tracked_offset > 0) { complete_current_block (p, p->tracked_offset); } } /* Returns a pointer to the block info for the completed block at the * head of the queue, and extracts the bytes from the adapter if requested. * Caller should move to the next block by calling mpeg_packetiser_next_block * afterward. */ MPEGBlockInfo * mpeg_packetiser_get_block (MPEGPacketiser * p, GstBuffer ** buf) { MPEGBlockInfo *block; if (buf) *buf = NULL; if (G_UNLIKELY (p->first_block_idx == -1)) { return NULL; /* No complete blocks to discard */ } /* p->first_block_idx can't get set != -1 unless some block storage got * allocated */ g_assert (p->blocks != NULL && p->n_blocks != 0); block = p->blocks + p->first_block_idx; /* Can only get the buffer out once, so we'll return NULL on later attempts */ if (buf != NULL && block->length > 0 && p->adapter_offset <= block->offset) { /* Kick excess data out of the adapter */ if (p->adapter_offset < block->offset) { guint64 to_flush = block->offset - p->adapter_offset; g_assert (gst_adapter_available (p->adapter) >= to_flush); gst_adapter_flush (p->adapter, to_flush); p->adapter_offset += to_flush; } g_assert (gst_adapter_available (p->adapter) >= block->length); *buf = gst_adapter_take_buffer (p->adapter, block->length); p->adapter_offset += block->length; GST_BUFFER_TIMESTAMP (*buf) = block->ts; } return block; } /* Advance the first_block pointer to discard a completed block * from the queue */ void mpeg_packetiser_next_block (MPEGPacketiser * p) { gint next; MPEGBlockInfo *block; block = mpeg_packetiser_get_block (p, NULL); if (G_UNLIKELY (block == NULL)) return; /* No complete blocks to discard */ /* Update the statistics regarding the block we're discarding */ if (block->flags & MPEG_BLOCK_FLAG_PICTURE) p->n_pictures--; next = (p->first_block_idx + 1) % p->n_blocks; if (next == p->cur_block_idx) p->first_block_idx = -1; /* Discarding the last block */ else p->first_block_idx = next; } /* Set the Pixel Aspect Ratio in our hdr from a DAR code in the data */ static void set_par_from_dar (MPEGSeqHdr * hdr, guint8 asr_code) { /* Pixel_width = DAR_width * display_vertical_size */ /* Pixel_height = DAR_height * display_horizontal_size */ switch (asr_code) { case 0x02: /* 3:4 DAR = 4:3 pixels */ hdr->par_w = 4 * hdr->height; hdr->par_h = 3 * hdr->width; break; case 0x03: /* 9:16 DAR */ hdr->par_w = 16 * hdr->height; hdr->par_h = 9 * hdr->width; break; case 0x04: /* 1:2.21 DAR */ hdr->par_w = 221 * hdr->height; hdr->par_h = 100 * hdr->width; break; case 0x01: /* Square pixels */ default: hdr->par_w = hdr->par_h = 1; break; } } static void set_fps_from_code (MPEGSeqHdr * hdr, guint8 fps_code) { const gint framerates[][2] = { {30, 1}, {24000, 1001}, {24, 1}, {25, 1}, {30000, 1001}, {30, 1}, {50, 1}, {60000, 1001}, {60, 1}, {30, 1} }; if (fps_code < 10) { hdr->fps_n = framerates[fps_code][0]; hdr->fps_d = framerates[fps_code][1]; } else { /* Force a valid framerate */ hdr->fps_n = 30000; hdr->fps_d = 1001; } } static gboolean mpeg_util_parse_extension_packet (MPEGSeqHdr * hdr, guint8 * data, guint8 * end) { guint8 ext_code; if (G_UNLIKELY (data >= end)) return FALSE; /* short extension packet */ ext_code = data[0] >> 4; switch (ext_code) { case MPEG_PACKET_EXT_SEQUENCE: { /* Parse a Sequence Extension */ gboolean low_delay; guint8 chroma_format; guint8 horiz_size_ext, vert_size_ext; guint8 fps_n_ext, fps_d_ext; if (G_UNLIKELY ((end - data) < 6)) /* need at least 10 bytes, minus 4 for the start code 000001b5 */ return FALSE; hdr->profile = data[0] & 0x0f; /* profile (0:2) + escape bit (3) */ hdr->level = (data[1] >> 4) & 0x0f; hdr->progressive = data[1] & 0x08; chroma_format = (data[1] >> 2) & 0x03; horiz_size_ext = ((data[1] << 1) & 0x02) | ((data[2] >> 7) & 0x01); vert_size_ext = (data[2] >> 5) & 0x03; low_delay = data[5] >> 7; fps_n_ext = (data[5] >> 5) & 0x03; fps_d_ext = data[5] & 0x1f; hdr->fps_n *= (fps_n_ext + 1); hdr->fps_d *= (fps_d_ext + 1); hdr->width += (horiz_size_ext << 12); hdr->height += (vert_size_ext << 12); break; } default: break; } return TRUE; } gboolean mpeg_util_parse_sequence_hdr (MPEGSeqHdr * hdr, guint8 * data, guint8 * end) { guint32 code; guint8 dar_idx, fps_idx; guint32 sync_word = 0xffffffff; gboolean constrained_flag; gboolean load_intra_flag; gboolean load_non_intra_flag; if (G_UNLIKELY ((end - data) < 12)) return FALSE; /* Too small to be a sequence header */ code = GST_READ_UINT32_BE (data); if (G_UNLIKELY (code != (0x00000100 | MPEG_PACKET_SEQUENCE))) return FALSE; /* Skip the sync word */ data += 4; /* Parse the MPEG 1 bits */ hdr->mpeg_version = 1; code = GST_READ_UINT32_BE (data); hdr->width = (code >> 20) & 0xfff; hdr->height = (code >> 8) & 0xfff; dar_idx = (code >> 4) & 0xf; set_par_from_dar (hdr, dar_idx); fps_idx = code & 0xf; set_fps_from_code (hdr, fps_idx); hdr->bitrate = ((data[6] >> 6) | (data[5] << 2) | (data[4] << 10)); if (hdr->bitrate == 0x3ffff) { /* VBR stream */ hdr->bitrate = 0; } else { /* Value in header is in units of 400 bps */ hdr->bitrate *= 400; } constrained_flag = (data[7] >> 2) & 0x01; load_intra_flag = (data[7] >> 1) & 0x01; if (load_intra_flag) { if (G_UNLIKELY ((end - data) < 64)) return FALSE; data += 64; } load_non_intra_flag = data[7] & 0x01; if (load_non_intra_flag) { if (G_UNLIKELY ((end - data) < 64)) return FALSE; data += 64; } /* Advance past the rest of the MPEG-1 header */ data += 8; /* Read MPEG-2 sequence extensions */ data = mpeg_util_find_start_code (&sync_word, data, end); while (data != NULL) { if (G_UNLIKELY (data >= end)) return FALSE; /* data points at the last byte of the start code */ if (data[0] == MPEG_PACKET_EXTENSION) { if (!mpeg_util_parse_extension_packet (hdr, data + 1, end)) return FALSE; hdr->mpeg_version = 2; } data = mpeg_util_find_start_code (&sync_word, data, end); } return TRUE; } gboolean mpeg_util_parse_picture_hdr (MPEGPictureHdr * hdr, guint8 * data, guint8 * end) { guint32 code; if (G_UNLIKELY ((end - data) < 6)) return FALSE; /* Packet too small */ code = GST_READ_UINT32_BE (data); if (G_UNLIKELY (code != (0x00000100 | MPEG_PACKET_PICTURE))) return FALSE; /* Skip the start code */ data += 4; hdr->pic_type = (data[1] >> 3) & 0x07; if (hdr->pic_type == 0 || hdr->pic_type > 4) return FALSE; /* Corrupted picture packet */ return TRUE; }