qt-faststart is a tool that moves the 'moov' to the start of file, reducing startup latency.

This version handles 'free' atoms, which are produced by mp4box and other tools, but impact ffmpeg seeks on playback.
The code follows ffmpeg coding standards.

BUG=17304
TEST=instrument seeks or measure latency performance and play videos with and without qt-faststart applied to the data.

Review URL: http://codereview.chromium.org/149439

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@21150 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 333 insertions, 0 deletions

diff --git a/media/media.gyp b/media/media.gyp
index 989d16b..0d5821f 100644
--- a/media/media.gyp
+++ b/media/media.gyp
@@ -210,6 +210,13 @@
         'tools/wav_ola_test.cc'
       ],
     },
+    {
+      'target_name': 'qt_faststart',
+      'type': 'executable',
+      'sources': [
+        'tools/qt-faststart.c'
+      ],
+    },
   ],
   'conditions': [
     ['OS=="win"', {
diff --git a/media/tools/qt-faststart.c b/media/tools/qt-faststart.c
new file mode 100644
index 0000000..8e85825
--- /dev/null
+++ b/media/tools/qt-faststart.c
@@ -0,0 +1,326 @@
+/*
+ * qt-faststart.c, v0.2
+ * by Mike Melanson (melanson@pcisys.net)
+ * patch by Frank Barchard, to remove last FREE atom.
+ * This file is placed in the public domain. Use the program however you
+ * see fit.
+ *
+ * This utility rearranges a Quicktime file such that the moov atom
+ * is in front of the data, thus facilitating network streaming.
+ *
+ * To compile this program, start from the base directory from which you
+ * are building FFmpeg and type:
+ *  make tools/qt-faststart
+ * The qt-faststart program will be built in the tools/ directory. If you
+ * do not build the program in this manner, correct results are not
+ * guaranteed, particularly on 64-bit platforms.
+ * Invoke the program with:
+ *  qt-faststart <infile.mov> <outfile.mov>
+ *
+ * Notes: Quicktime files can come in many configurations of top-level
+ * atoms. This utility stipulates that the very last atom in the file needs
+ * to be a moov atom. When given such a file, this utility will rearrange
+ * the top-level atoms by shifting the moov atom from the back of the file
+ * to the front, and patch the chunk offsets along the way. This utility
+ * presently only operates on uncompressed moov atoms.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#ifndef _MSC_VER
+#include <inttypes.h>
+#else
+#pragma warning(push,1)
+#define PRIu64 "I64u"
+#define uint64_t unsigned __int64
+#define uint32_t unsigned int
+#define uint8_t unsigned char
+#define ftello _ftelli64
+#define fseeko _fseeki64
+#endif
+
+#ifdef __MINGW32__
+#define fseeko(x,y,z)  fseeko64(x,y,z)
+#define ftello(x)      ftello64(x)
+#endif
+
+#define BE_16(x) ((((uint8_t*)(x))[0] << 8) | ((uint8_t*)(x))[1])
+#define BE_32(x) ((((uint8_t*)(x))[0] << 24) | \
+                  (((uint8_t*)(x))[1] << 16) | \
+                  (((uint8_t*)(x))[2] << 8) | \
+                   ((uint8_t*)(x))[3])
+#define BE_64(x) (((uint64_t)(((uint8_t*)(x))[0]) << 56) | \
+                  ((uint64_t)(((uint8_t*)(x))[1]) << 48) | \
+                  ((uint64_t)(((uint8_t*)(x))[2]) << 40) | \
+                  ((uint64_t)(((uint8_t*)(x))[3]) << 32) | \
+                  ((uint64_t)(((uint8_t*)(x))[4]) << 24) | \
+                  ((uint64_t)(((uint8_t*)(x))[5]) << 16) | \
+                  ((uint64_t)(((uint8_t*)(x))[6]) << 8) | \
+                  ((uint64_t)((uint8_t*)(x))[7]))
+
+#define BE_FOURCC( ch0, ch1, ch2, ch3 )             \
+        ( (uint32_t)(unsigned char)(ch3) |          \
+        ( (uint32_t)(unsigned char)(ch2) << 8 ) |   \
+        ( (uint32_t)(unsigned char)(ch1) << 16 ) |  \
+        ( (uint32_t)(unsigned char)(ch0) << 24 ) )
+
+#define QT_ATOM BE_FOURCC
+/* top level atoms */
+#define FREE_ATOM QT_ATOM('f', 'r', 'e', 'e')
+#define JUNK_ATOM QT_ATOM('j', 'u', 'n', 'k')
+#define MDAT_ATOM QT_ATOM('m', 'd', 'a', 't')
+#define MOOV_ATOM QT_ATOM('m', 'o', 'o', 'v')
+#define PNOT_ATOM QT_ATOM('p', 'n', 'o', 't')
+#define SKIP_ATOM QT_ATOM('s', 'k', 'i', 'p')
+#define WIDE_ATOM QT_ATOM('w', 'i', 'd', 'e')
+#define PICT_ATOM QT_ATOM('P', 'I', 'C', 'T')
+#define FTYP_ATOM QT_ATOM('f', 't', 'y', 'p')
+#define UUID_ATOM QT_ATOM('u', 'u', 'i', 'd')
+
+#define CMOV_ATOM QT_ATOM('c', 'm', 'o', 'v')
+#define STCO_ATOM QT_ATOM('s', 't', 'c', 'o')
+#define CO64_ATOM QT_ATOM('c', 'o', '6', '4')
+
+#define ATOM_PREAMBLE_SIZE 8
+#define COPY_BUFFER_SIZE 1024
+
+int main(int argc, char *argv[])
+{
+    FILE *infile = 0;
+    FILE *outfile = 0;
+    unsigned char atom_bytes[ATOM_PREAMBLE_SIZE];
+    uint32_t atom_type = 0;
+    uint64_t atom_size = 0;
+    uint64_t last_offset;
+    unsigned char *moov_atom = 0;
+    unsigned char *ftyp_atom = 0;
+    uint64_t moov_atom_size;
+    uint64_t ftyp_atom_size = 0;
+    uint64_t i, j;
+    uint32_t offset_count;
+    uint64_t current_offset;
+    uint64_t start_offset = 0;
+    unsigned char copy_buffer[COPY_BUFFER_SIZE];
+    int bytes_to_copy;
+    uint32_t last_atom_type = 0;
+    uint64_t last_atom_size = 0;
+    uint64_t last_atom_offset = 0;
+    uint64_t atom_offset;
+    int just_remove_free = 0;
+    int return_code = 1;
+
+    if (argc != 3) {
+        printf ("Usage: qt_faststart <infile.mov> <outfile.mov>\n");
+        goto exit_cleanup;
+    }
+
+    infile = fopen(argv[1], "rb");
+    if (!infile) {
+        perror(argv[1]);
+        goto exit_cleanup;
+    }
+
+    /* traverse through the atoms in the file to make sure that 'moov' is
+     * at the end */
+    while (!feof(infile)) {
+        if (fread(atom_bytes, ATOM_PREAMBLE_SIZE, 1, infile) != 1) {
+            break;
+        }
+        atom_size = (uint32_t)BE_32(&atom_bytes[0]);
+        atom_type = BE_32(&atom_bytes[4]);
+        atom_offset = ftello(infile) - ATOM_PREAMBLE_SIZE;
+
+        /* keep ftyp atom */
+        if (atom_type == FTYP_ATOM) {
+            ftyp_atom_size = atom_size;
+            ftyp_atom = malloc(ftyp_atom_size);
+            if (!ftyp_atom) {
+                printf ("could not allocate 0x%llX byte for ftyp atom\n",
+                        atom_size);
+                goto exit_cleanup;
+            }
+            fseeko(infile, -ATOM_PREAMBLE_SIZE, SEEK_CUR);
+            if (fread(ftyp_atom, atom_size, 1, infile) != 1) {
+                perror(argv[1]);
+                goto exit_cleanup;
+            }
+            start_offset = ftello(infile);
+        } else {
+        /* 64-bit special case */
+        if (atom_size == 1) {
+            if (fread(atom_bytes, ATOM_PREAMBLE_SIZE, 1, infile) != 1) {
+                break;
+            }
+            atom_size = BE_64(&atom_bytes[0]);
+            fseeko(infile, atom_size - ATOM_PREAMBLE_SIZE * 2, SEEK_CUR);
+        } else {
+            fseeko(infile, atom_size - ATOM_PREAMBLE_SIZE, SEEK_CUR);
+        }
+        }
+
+        printf("%c%c%c%c %10"PRIu64" %"PRIu64"\n",
+               (atom_type >> 24) & 255,
+               (atom_type >> 16) & 255,
+               (atom_type >>  8) & 255,
+               (atom_type >>  0) & 255,
+               (unsigned long long ) atom_offset,
+               (unsigned long long ) atom_size);
+
+        if ((atom_type != FREE_ATOM) &&
+            (atom_type != JUNK_ATOM) &&
+            (atom_type != MDAT_ATOM) &&
+            (atom_type != MOOV_ATOM) &&
+            (atom_type != PNOT_ATOM) &&
+            (atom_type != SKIP_ATOM) &&
+            (atom_type != WIDE_ATOM) &&
+            (atom_type != PICT_ATOM) &&
+            (atom_type != UUID_ATOM) &&
+            (atom_type != FTYP_ATOM)) {
+            printf ("encountered non-QT top-level atom (is this a Quicktime file?)\n");
+            break;
+        }
+        if ((atom_type != FREE_ATOM)) {
+            last_atom_size = atom_size;
+            last_atom_type = atom_type;
+            last_atom_offset = ftello(infile) - last_atom_size;
+        }
+        if ((atom_type != FREE_ATOM) && (atom_type != MOOV_ATOM))
+            last_offset = ftello(infile);
+    }
+
+    if (last_atom_type == MOOV_ATOM) {
+
+        /* moov atom was, in fact, the last atom in the chunk; load the whole
+         * moov atom */
+        fseeko(infile, last_atom_offset, SEEK_SET);
+        moov_atom_size = last_atom_size;
+        moov_atom = malloc(moov_atom_size);
+        if (!moov_atom) {
+            printf ("could not allocate 0x%llX byte for moov atom\n",
+                atom_size);
+            goto exit_cleanup;
+        }
+        if (fread(moov_atom, moov_atom_size, 1, infile) != 1) {
+            perror(argv[1]);
+            goto exit_cleanup;
+        }
+
+        /* this utility does not support compressed atoms yet, so disqualify
+         * files with compressed QT atoms */
+        if (BE_32(&moov_atom[12]) == CMOV_ATOM) {
+            printf ("this utility does not support compressed moov atoms yet\n");
+            goto exit_cleanup;
+        }
+
+        /* crawl through the moov chunk in search of stco or co64 atoms */
+        for (i = 4; i < moov_atom_size - 4; i++) {
+            atom_type = BE_32(&moov_atom[i]);
+            if (atom_type == STCO_ATOM) {
+                printf (" patching stco atom...\n");
+                atom_size = BE_32(&moov_atom[i - 4]);
+                if (i + atom_size - 4 > moov_atom_size) {
+                    printf (" bad atom size\n");
+                    free(moov_atom);
+                    return 1;
+                }
+                offset_count = BE_32(&moov_atom[i + 8]);
+                for (j = 0; j < offset_count; j++) {
+                    current_offset = BE_32(&moov_atom[i + 12 + j * 4]);
+                    current_offset += moov_atom_size;
+                    moov_atom[i + 12 + j * 4 + 0] = (current_offset >> 24) & 0xFF;
+                    moov_atom[i + 12 + j * 4 + 1] = (current_offset >> 16) & 0xFF;
+                    moov_atom[i + 12 + j * 4 + 2] = (current_offset >>  8) & 0xFF;
+                    moov_atom[i + 12 + j * 4 + 3] = (current_offset >>  0) & 0xFF;
+                }
+                i += atom_size - 4;
+            } else if (atom_type == CO64_ATOM) {
+                printf (" patching co64 atom...\n");
+                atom_size = BE_32(&moov_atom[i - 4]);
+                if (i + atom_size - 4 > moov_atom_size) {
+                    printf (" bad atom size\n");
+                    free(moov_atom);
+                    return 1;
+                }
+                offset_count = BE_32(&moov_atom[i + 8]);
+                for (j = 0; j < offset_count; j++) {
+                    current_offset = BE_64(&moov_atom[i + 12 + j * 8]);
+                    current_offset += moov_atom_size;
+                    moov_atom[i + 12 + j * 8 + 0] = (current_offset >> 56) & 0xFF;
+                    moov_atom[i + 12 + j * 8 + 1] = (current_offset >> 48) & 0xFF;
+                    moov_atom[i + 12 + j * 8 + 2] = (current_offset >> 40) & 0xFF;
+                    moov_atom[i + 12 + j * 8 + 3] = (current_offset >> 32) & 0xFF;
+                    moov_atom[i + 12 + j * 8 + 4] = (current_offset >> 24) & 0xFF;
+                    moov_atom[i + 12 + j * 8 + 5] = (current_offset >> 16) & 0xFF;
+                    moov_atom[i + 12 + j * 8 + 6] = (current_offset >>  8) & 0xFF;
+                    moov_atom[i + 12 + j * 8 + 7] = (current_offset >>  0) & 0xFF;
+                }
+                i += atom_size - 4;
+            }
+        }
+    } else {
+        if (atom_type == FREE_ATOM) {
+            printf ("free atom at %"PRIu64" removed.\n", (unsigned long long ) last_offset);
+            just_remove_free = 1;
+        } else {
+            printf ("Last atom in file was not a moov or free atom.  Skipping.\n");
+            goto exit_cleanup;
+        }
+    }
+
+    outfile = fopen(argv[2], "wb");
+    if (!outfile) {
+        perror(argv[2]);
+        goto exit_cleanup;
+    }
+
+    /* dump the same ftyp atom */
+    if (ftyp_atom_size > 0) {
+        printf (" writing ftyp atom...\n");
+        if (fwrite(ftyp_atom, ftyp_atom_size, 1, outfile) != 1) {
+            perror(argv[2]);
+            goto exit_cleanup;
+        }
+    }
+
+    if (!just_remove_free) {
+        /* dump the new moov atom */
+        printf (" writing moov atom...\n");
+        if (fwrite(moov_atom, moov_atom_size, 1, outfile) != 1) {
+            perror(argv[2]);
+            goto exit_cleanup;
+        }
+    }
+
+    /* copy the remainder of the infile, from offset 0 -> last_offset - 1 */
+    printf (" copying rest of file: %"PRIu64"..%"PRIu64"\n", start_offset, last_offset);
+    fseeko(infile, start_offset, SEEK_SET);
+    last_offset -= start_offset;  /* Amount to copy */
+    while (last_offset > 0) {
+        if (last_offset > COPY_BUFFER_SIZE)
+            bytes_to_copy = COPY_BUFFER_SIZE;
+        else
+            bytes_to_copy = last_offset;
+
+        if (fread(copy_buffer, bytes_to_copy, 1, infile) != 1) {
+            perror(argv[1]);
+            goto exit_cleanup;
+        }
+        if (fwrite(copy_buffer, bytes_to_copy, 1, outfile) != 1) {
+            perror(argv[2]);
+            goto exit_cleanup;
+        }
+        last_offset -= bytes_to_copy;
+    }
+    return_code = 0;
+
+exit_cleanup:
+    if (infile)
+        fclose(infile);
+    if (outfile)
+        fclose(outfile);
+    if (moov_atom)
+        free(moov_atom);
+    if (ftyp_atom)
+        free(ftyp_atom);
+    return return_code;
+}