/* * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "libavutil/avassert.h" #include "cbs.h" #include "cbs_internal.h" #include "cbs_mpeg2.h" #include "internal.h" #define HEADER(name) do { \ ff_cbs_trace_header(ctx, name); \ } while (0) #define CHECK(call) do { \ err = (call); \ if (err < 0) \ return err; \ } while (0) #define FUNC_NAME(rw, codec, name) cbs_ ## codec ## _ ## rw ## _ ## name #define FUNC_MPEG2(rw, name) FUNC_NAME(rw, mpeg2, name) #define FUNC(name) FUNC_MPEG2(READWRITE, name) #define READ #define READWRITE read #define RWContext GetBitContext #define xui(width, name, var) do { \ uint32_t value = 0; \ CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \ &value, 0, (1 << width) - 1)); \ var = value; \ } while (0) #define ui(width, name) \ xui(width, name, current->name) #define marker_bit() do { \ av_unused uint32_t one; \ CHECK(ff_cbs_read_unsigned(ctx, rw, 1, "marker_bit", &one, 1, 1)); \ } while (0) #define nextbits(width, compare, var) \ (get_bits_left(rw) >= width && \ (var = show_bits(rw, width)) == (compare)) #include "cbs_mpeg2_syntax_template.c" #undef READ #undef READWRITE #undef RWContext #undef xui #undef ui #undef marker_bit #undef nextbits #define WRITE #define READWRITE write #define RWContext PutBitContext #define xui(width, name, var) do { \ CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \ var, 0, (1 << width) - 1)); \ } while (0) #define ui(width, name) \ xui(width, name, current->name) #define marker_bit() do { \ CHECK(ff_cbs_write_unsigned(ctx, rw, 1, "marker_bit", 1, 1, 1)); \ } while (0) #define nextbits(width, compare, var) (var) #include "cbs_mpeg2_syntax_template.c" #undef READ #undef READWRITE #undef RWContext #undef xui #undef ui #undef marker_bit #undef nextbits static void cbs_mpeg2_free_user_data(void *unit, uint8_t *content) { MPEG2RawUserData *user = (MPEG2RawUserData*)content; av_buffer_unref(&user->user_data_ref); av_freep(&content); } static void cbs_mpeg2_free_slice(void *unit, uint8_t *content) { MPEG2RawSlice *slice = (MPEG2RawSlice*)content; av_buffer_unref(&slice->header.extra_information_ref); av_buffer_unref(&slice->data_ref); av_freep(&content); } static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx, CodedBitstreamFragment *frag, int header) { const uint8_t *start, *end; uint8_t *unit_data; uint32_t start_code = -1, next_start_code = -1; size_t unit_size; int err, i, unit_type; start = avpriv_find_start_code(frag->data, frag->data + frag->data_size, &start_code); for (i = 0;; i++) { end = avpriv_find_start_code(start, frag->data + frag->data_size, &next_start_code); unit_type = start_code & 0xff; // The start and end pointers point at to the byte following the // start_code_identifier in the start code that they found. if (end == frag->data + frag->data_size) { // We didn't find a start code, so this is the final unit. unit_size = end - (start - 1); } else { // Unit runs from start to the beginning of the start code // pointed to by end (including any padding zeroes). unit_size = (end - 4) - (start - 1); } unit_data = (uint8_t *)start - 1; err = ff_cbs_insert_unit_data(ctx, frag, i, unit_type, unit_data, unit_size, frag->data_ref); if (err < 0) return err; if (end == frag->data + frag->data_size) break; start_code = next_start_code; start = end; } return 0; } static int cbs_mpeg2_read_unit(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit) { GetBitContext gbc; int err; err = init_get_bits(&gbc, unit->data, 8 * unit->data_size); if (err < 0) return err; if (MPEG2_START_IS_SLICE(unit->type)) { MPEG2RawSlice *slice; int pos, len; err = ff_cbs_alloc_unit_content(ctx, unit, sizeof(*slice), &cbs_mpeg2_free_slice); if (err < 0) return err; slice = unit->content; err = cbs_mpeg2_read_slice_header(ctx, &gbc, &slice->header); if (err < 0) return err; pos = get_bits_count(&gbc); len = unit->data_size; slice->data_size = len - pos / 8; slice->data_ref = av_buffer_alloc(slice->data_size + AV_INPUT_BUFFER_PADDING_SIZE); if (!slice->data_ref) return AVERROR(ENOMEM); slice->data = slice->data_ref->data; memcpy(slice->data, unit->data + pos / 8, slice->data_size); memset(slice->data + slice->data_size, 0, AV_INPUT_BUFFER_PADDING_SIZE); slice->data_bit_start = pos % 8; } else { switch (unit->type) { #define START(start_code, type, read_func, free_func) \ case start_code: \ { \ type *header; \ err = ff_cbs_alloc_unit_content(ctx, unit, \ sizeof(*header), free_func); \ if (err < 0) \ return err; \ header = unit->content; \ err = cbs_mpeg2_read_ ## read_func(ctx, &gbc, header); \ if (err < 0) \ return err; \ } \ break; START(0x00, MPEG2RawPictureHeader, picture_header, NULL); START(0xb2, MPEG2RawUserData, user_data, &cbs_mpeg2_free_user_data); START(0xb3, MPEG2RawSequenceHeader, sequence_header, NULL); START(0xb5, MPEG2RawExtensionData, extension_data, NULL); START(0xb8, MPEG2RawGroupOfPicturesHeader, group_of_pictures_header, NULL); #undef START default: av_log(ctx->log_ctx, AV_LOG_ERROR, "Unknown start code %02"PRIx32".\n", unit->type); return AVERROR_INVALIDDATA; } } return 0; } static int cbs_mpeg2_write_header(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit, PutBitContext *pbc) { int err; switch (unit->type) { #define START(start_code, type, func) \ case start_code: \ err = cbs_mpeg2_write_ ## func(ctx, pbc, unit->content); \ break; START(0x00, MPEG2RawPictureHeader, picture_header); START(0xb2, MPEG2RawUserData, user_data); START(0xb3, MPEG2RawSequenceHeader, sequence_header); START(0xb5, MPEG2RawExtensionData, extension_data); START(0xb8, MPEG2RawGroupOfPicturesHeader, group_of_pictures_header); #undef START default: av_log(ctx->log_ctx, AV_LOG_ERROR, "Write unimplemented for start " "code %02"PRIx32".\n", unit->type); return AVERROR_PATCHWELCOME; } return err; } static int cbs_mpeg2_write_slice(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit, PutBitContext *pbc) { MPEG2RawSlice *slice = unit->content; GetBitContext gbc; size_t bits_left; int err; err = cbs_mpeg2_write_slice_header(ctx, pbc, &slice->header); if (err < 0) return err; if (slice->data) { if (slice->data_size * 8 + 8 > put_bits_left(pbc)) return AVERROR(ENOSPC); init_get_bits(&gbc, slice->data, slice->data_size * 8); skip_bits_long(&gbc, slice->data_bit_start); while (get_bits_left(&gbc) > 15) put_bits(pbc, 16, get_bits(&gbc, 16)); bits_left = get_bits_left(&gbc); put_bits(pbc, bits_left, get_bits(&gbc, bits_left)); // Align with zeroes. while (put_bits_count(pbc) % 8 != 0) put_bits(pbc, 1, 0); } return 0; } static int cbs_mpeg2_write_unit(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit) { CodedBitstreamMPEG2Context *priv = ctx->priv_data; PutBitContext pbc; int err; if (!priv->write_buffer) { // Initial write buffer size is 1MB. priv->write_buffer_size = 1024 * 1024; reallocate_and_try_again: err = av_reallocp(&priv->write_buffer, priv->write_buffer_size); if (err < 0) { av_log(ctx->log_ctx, AV_LOG_ERROR, "Unable to allocate a " "sufficiently large write buffer (last attempt " "%"SIZE_SPECIFIER" bytes).\n", priv->write_buffer_size); return err; } } init_put_bits(&pbc, priv->write_buffer, priv->write_buffer_size); if (unit->type >= 0x01 && unit->type <= 0xaf) err = cbs_mpeg2_write_slice(ctx, unit, &pbc); else err = cbs_mpeg2_write_header(ctx, unit, &pbc); if (err == AVERROR(ENOSPC)) { // Overflow. priv->write_buffer_size *= 2; goto reallocate_and_try_again; } if (err < 0) { // Write failed for some other reason. return err; } if (put_bits_count(&pbc) % 8) unit->data_bit_padding = 8 - put_bits_count(&pbc) % 8; else unit->data_bit_padding = 0; unit->data_size = (put_bits_count(&pbc) + 7) / 8; flush_put_bits(&pbc); err = ff_cbs_alloc_unit_data(ctx, unit, unit->data_size); if (err < 0) return err; memcpy(unit->data, priv->write_buffer, unit->data_size); return 0; } static int cbs_mpeg2_assemble_fragment(CodedBitstreamContext *ctx, CodedBitstreamFragment *frag) { uint8_t *data; size_t size, dp; int i; size = 0; for (i = 0; i < frag->nb_units; i++) size += 3 + frag->units[i].data_size; frag->data_ref = av_buffer_alloc(size + AV_INPUT_BUFFER_PADDING_SIZE); if (!frag->data_ref) return AVERROR(ENOMEM); data = frag->data_ref->data; dp = 0; for (i = 0; i < frag->nb_units; i++) { CodedBitstreamUnit *unit = &frag->units[i]; data[dp++] = 0; data[dp++] = 0; data[dp++] = 1; memcpy(data + dp, unit->data, unit->data_size); dp += unit->data_size; } av_assert0(dp == size); memset(data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE); frag->data = data; frag->data_size = size; return 0; } static void cbs_mpeg2_close(CodedBitstreamContext *ctx) { CodedBitstreamMPEG2Context *priv = ctx->priv_data; av_freep(&priv->write_buffer); } const CodedBitstreamType ff_cbs_type_mpeg2 = { .codec_id = AV_CODEC_ID_MPEG2VIDEO, .priv_data_size = sizeof(CodedBitstreamMPEG2Context), .split_fragment = &cbs_mpeg2_split_fragment, .read_unit = &cbs_mpeg2_read_unit, .write_unit = &cbs_mpeg2_write_unit, .assemble_fragment = &cbs_mpeg2_assemble_fragment, .close = &cbs_mpeg2_close, };